WIP: working copy-no-compositor path

chrome/browser/android/vr_shell/vr_shell_gl.cc

Index: chrome/browser/android/vr_shell/vr_shell_gl.cc
diff --git a/chrome/browser/android/vr_shell/vr_shell_gl.cc b/chrome/browser/android/vr_shell/vr_shell_gl.cc
index 55a1c7ee9d4ff363953955bc80793b53791daf34..73291b9c5e3fd393cd210ce3e98f8a5284134cba 100644
--- a/chrome/browser/android/vr_shell/vr_shell_gl.cc
+++ b/chrome/browser/android/vr_shell/vr_shell_gl.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/android/vr_shell/vr_shell_gl.h"
 
+#include "base/android/jni_android.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ -23,6 +24,8 @@
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_surface.h"
 #include "ui/gl/init/gl_factory.h"
+#include "gpu/ipc/common/gpu_surface_tracker.h"
+#include "gpu/ipc/common/surface_handle.h"
 
 namespace vr_shell {
 
@@ -32,6 +35,11 @@ static constexpr long kPredictionTimeWithoutVsyncNanos = 50000000;
 
 static constexpr float kZNear = 0.1f;
 static constexpr float kZFar = 1000.0f;
+#include <android/native_window.h>
+#include <android/native_window_jni.h>
+
+#include <iomanip>
+
 
 // Screen angle in degrees. 0 = vertical, positive = top closer.
 static constexpr float kDesktopScreenTiltDefault = 0;
@@ -81,10 +89,6 @@ static constexpr gvr::Rectf kHeadlockedBufferFov = {20.f, 20.f, 20.f, 20.f};
 static constexpr int kViewportListPrimaryOffset = 0;
 static constexpr int kViewportListHeadlockedOffset = 2;
 
-// Magic numbers used to mark valid pose index values encoded in frame
-// data. Must match the magic numbers used in blink's VRDisplay.cpp.
-static constexpr std::array<uint8_t, 2> kWebVrPosePixelMagicNumbers{{42, 142}};
-
 float Distance(const gvr::Vec3f& vec1, const gvr::Vec3f& vec2) {
   float xdiff = (vec1.x - vec2.x);
   float ydiff = (vec1.y - vec2.y);
@@ -141,39 +145,26 @@ enum class ViewerType {
   VIEWER_TYPE_MAX,
 };
 
-int GetPixelEncodedPoseIndexByte() {
-  TRACE_EVENT0("gpu", "VrShellGl::GetPixelEncodedPoseIndex");
-  // Read the pose index encoded in a bottom left pixel as color values.
-  // See also third_party/WebKit/Source/modules/vr/VRDisplay.cpp which
-  // encodes the pose index, and device/vr/android/gvr/gvr_device.cc
-  // which tracks poses. Returns the low byte (0..255) if valid, or -1
-  // if not valid due to bad magic number.
-  uint8_t pixels[4];
-  // Assume we're reading from the framebuffer we just wrote to.
-  // That's true currently, we may need to use glReadBuffer(GL_BACK)
-  // or equivalent if the rendering setup changes in the future.
-  glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
-
-  // Check for the magic number written by VRDevice.cpp on submit.
-  // This helps avoid glitches from garbage data in the render
-  // buffer that can appear during initialization or resizing. These
-  // often appear as flashes of all-black or all-white pixels.
-  if (pixels[1] == kWebVrPosePixelMagicNumbers[0] &&
-      pixels[2] == kWebVrPosePixelMagicNumbers[1]) {
-    // Pose is good.
-    return pixels[0];
-  }
-  VLOG(1) << "WebVR: reject decoded pose index " << (int)pixels[0] <<
-      ", bad magic number " << (int)pixels[1] << ", " << (int)pixels[2];
-  return -1;
-}
+}  // namespace
 
 int64_t TimeInMicroseconds() {
   return std::chrono::duration_cast<std::chrono::microseconds>(
       std::chrono::steady_clock::now().time_since_epoch()).count();
 }
 
-}  // namespace
+uint32_t GetPixelEncodedPoseIndex() {
+  TRACE_EVENT0("gpu", "VrShell::GetPixelEncodedPoseIndex");
+  // Read the pose index encoded in a bottom left pixel as color values.
+  // See also third_party/WebKit/Source/modules/vr/VRDisplay.cpp which
+  // encodes the pose index, and device/vr/android/gvr/gvr_device.cc
+  // which tracks poses.
+  uint8_t pixels[4];
+  // Assume we're reading from the framebuffer we just wrote to.
+  // That's true currently, we may need to use glReadBuffer(GL_BACK)
+  // or equivalent if the rendering setup changes in the future.
+  glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+  return pixels[0] | (pixels[1] << 8) | (pixels[2] << 16);
+}
 
 VrShellGl::VrShellGl(
     const base::WeakPtr<VrShell>& weak_vr_shell,
@@ -202,13 +193,19 @@ bool VrShellGl::Initialize() {
   gvr::Mat4f identity;
   SetIdentityM(identity);
   webvr_head_pose_.resize(kPoseRingBufferSize, identity);
-  webvr_head_pose_valid_.resize(kPoseRingBufferSize, false);
+  webvr_time_frame_start_.resize(kPoseRingBufferSize, 0.0);
+  webvr_time_get_pose_.resize(kPoseRingBufferSize, 0.0);
+  webvr_time_got_pose_.resize(kPoseRingBufferSize, 0.0);
+  webvr_time_submit_.resize(kPoseRingBufferSize, 0.0);
+  webvr_time_surfaced_.resize(kPoseRingBufferSize, 0.0);
+  webvr_time_acquired_.resize(kPoseRingBufferSize, 0.0);
 
-  draw_task_.Reset(base::Bind(&VrShellGl::DrawFrame, base::Unretained(this)));
+  draw_task_.Reset(base::Bind(&VrShellGl::DrawFrame, base::Unretained(this), 0));
 
   scene_.reset(new UiScene);
 
   InitializeRenderer();
+  VLOG(1) << __FUNCTION__ << ": Destructor for presenting delegate and its gvr_api";
 
   ScheduleNextDrawFrame();
   return true;
@@ -250,24 +247,36 @@ bool VrShellGl::InitializeGl() {
     LOG(ERROR) << "No VSync Provider";
   }
 
-  unsigned int textures[2];
-  glGenTextures(2, textures);
+  unsigned int textures[3];
+  glGenTextures(3, textures);
   ui_texture_id_ = textures[0];
   content_texture_id_ = textures[1];
+  webvr_texture_id_ = textures[2];
+
   ui_surface_texture_ = gl::SurfaceTexture::Create(ui_texture_id_);
   content_surface_texture_ = gl::SurfaceTexture::Create(content_texture_id_);
+  webvr_surface_texture_ = gl::SurfaceTexture::Create(webvr_texture_id_);
+
   ui_surface_.reset(new gl::ScopedJavaSurface(ui_surface_texture_.get()));
   content_surface_.reset(new gl::ScopedJavaSurface(
       content_surface_texture_.get()));
+  webvr_surface_.reset(new gl::ScopedJavaSurface(
+      webvr_surface_texture_.get()));
+
   ui_surface_texture_->SetFrameAvailableCallback(base::Bind(
         &VrShellGl::OnUIFrameAvailable, weak_ptr_factory_.GetWeakPtr()));
   content_surface_texture_->SetFrameAvailableCallback(base::Bind(
         &VrShellGl::OnContentFrameAvailable, weak_ptr_factory_.GetWeakPtr()));
+  webvr_surface_texture_->SetFrameAvailableCallback(base::Bind(
+        &VrShellGl::OnWebVrFrameAvailable, weak_ptr_factory_.GetWeakPtr()));
 
   content_surface_texture_->SetDefaultBufferSize(
       content_tex_physical_size_.width, content_tex_physical_size_.height);
   ui_surface_texture_->SetDefaultBufferSize(ui_tex_physical_size_.width,
                                             ui_tex_physical_size_.height);
+  // Set a small default surface size for WebVR since we may not need it.
+  // Will be resized as needed.
+  webvr_surface_texture_->SetDefaultBufferSize(1, 1);
 
   main_thread_task_runner_->PostTask(FROM_HERE, base::Bind(
       &VrShell::SurfacesChanged, weak_vr_shell_,
@@ -284,6 +293,28 @@ void VrShellGl::OnContentFrameAvailable() {
   content_surface_texture_->UpdateTexImage();
 }
 
+void VrShellGl::OnWebVrFrameAvailable() {
+  if (!webvr_pending_poses_.size()) {
+    VLOG(2) << __FUNCTION__ << ": No pending pose, saving this frame for later";
+    ++webvr_already_available_frames_;
+    return;
+  }
+  uint32_t pose_index = webvr_pending_poses_.front();
+  webvr_pending_poses_.pop_front();
+  VLOG(2) << __FUNCTION__ << ": receiving WebVR frame " << pose_index;
+  webvr_surface_texture_->UpdateTexImage();
+  auto remaining_poses = webvr_pending_poses_.size();
+  if (remaining_poses > 0) {
+    VLOG(2) << __FUNCTION__ << ": still have " << remaining_poses << " pose(s) queued up.";
+  }
+  //long frameTimestamp = mWebVrSurfaceTexture.getTimestamp();
+  //if (frameTimestamp == 0) {
+  //  Log.w(TAG, "Invalid timestamp for frame on WebVR waiting list. This should not happen.");
+  //  return;
+  //}
+  DrawFrame(pose_index);
+}
+
 void VrShellGl::GvrInit(gvr_context* gvr_api) {
   gvr_api_ = gvr::GvrApi::WrapNonOwned(gvr_api);
   controller_.reset(new VrController(gvr_api));
@@ -306,21 +337,12 @@ void VrShellGl::GvrInit(gvr_context* gvr_api) {
 }
 
 void VrShellGl::InitializeRenderer() {
-  // While WebVR is going through the compositor path, it shares
-  // the same texture ID. This will change once it gets its own
-  // surface, but store it separately to avoid future confusion.
-  // TODO(klausw,crbug.com/655722): remove this.
-  webvr_texture_id_ = content_texture_id_;
-  // Out of paranoia, explicitly reset the "pose valid" flags to false
-  // from the GL thread. The constructor ran in the UI thread.
-  // TODO(klausw,crbug.com/655722): remove this.
-  webvr_head_pose_valid_.assign(kPoseRingBufferSize, false);
-
   gvr_api_->InitializeGl();
   std::vector<gvr::BufferSpec> specs;
   // For kFramePrimaryBuffer (primary VrShell and WebVR content)
   specs.push_back(gvr_api_->CreateBufferSpec());
   render_size_primary_ = specs[kFramePrimaryBuffer].GetSize();
+  render_size_primary_vrshell_ = render_size_primary_;
 
   // For kFrameHeadlockedBuffer (for WebVR insecure content warning).
   // Set this up at fixed resolution, the (smaller) FOV gets set below.
@@ -400,6 +422,7 @@ void VrShellGl::UpdateController(const gvr::Vec3f& forward_vector) {
     // Also send tap events for controller "touchpad click" events.
     if (touch_pending_ || controller_->ButtonUpHappened(
             gvr::ControllerButton::GVR_CONTROLLER_BUTTON_CLICK)) {
+      VLOG(1) << __FUNCTION__ << ": WebVR emulating Cardboard button";
       touch_pending_ = false;
       std::unique_ptr<WebGestureEvent> gesture(new WebGestureEvent());
       gesture->sourceDevice = blink::WebGestureDeviceTouchpad;
@@ -565,6 +588,21 @@ void VrShellGl::SendEventsToTarget(InputTarget input_target,
   }
 }
 
+static double getMonotonicTimestampMs() {
+  // TODO(klausw): replace with TimeInMicroseconds()?
+#if defined(OS_ANDROID)
+  // Android surfacetexture timestamp compatible timer? See:
+  //  http://androidxref.com/7.0.0_r1/xref/frameworks/native/libs/gui/Surface.cpp#370
+  //  http://androidxref.com/7.0.0_r1/xref/frameworks/rs/rsCppUtils.h#162
+  struct timespec t;
+  t.tv_sec = t.tv_nsec = 0;
+  clock_gettime(CLOCK_MONOTONIC, &t);
+  return t.tv_sec * 1e3 + t.tv_nsec * 1e-6;
+#else
+  return 0.0;
+#endif
+}
+
 void VrShellGl::SendGesture(InputTarget input_target,
                             std::unique_ptr<blink::WebInputEvent> event) {
   DCHECK(input_target != InputTarget::NONE);
@@ -577,45 +615,74 @@ void VrShellGl::SendGesture(InputTarget input_target,
                  base::Passed(std::move(event))));
 }
 
-void VrShellGl::SetGvrPoseForWebVr(const gvr::Mat4f& pose, uint32_t pose_num) {
-  webvr_head_pose_[pose_num % kPoseRingBufferSize] = pose;
-  webvr_head_pose_valid_[pose_num % kPoseRingBufferSize] = true;
+void VrShellGl::SetWebVRGvrPose(
+    const gvr::Mat4f& pose, uint32_t pose_index, int64_t pose_time_nanos) {
+  webvr_head_pose_[pose_index % kPoseRingBufferSize] = pose;
+  webvr_time_submit_[pose_index % kPoseRingBufferSize] = 0.0;
 }
 
-bool VrShellGl::WebVrPoseByteIsValid(int pose_index_byte) {
-  if (pose_index_byte < 0) {
-    return false;
-  }
-  if (!webvr_head_pose_valid_[pose_index_byte % kPoseRingBufferSize]) {
-    VLOG(1) << "WebVR: reject decoded pose index " << pose_index_byte <<
-        ", not a valid pose";
-    return false;
-  }
-  return true;
-}
-
-void VrShellGl::DrawFrame() {
-  TRACE_EVENT0("gpu", "VrShellGl::DrawFrame");
+void VrShellGl::DrawFrame(uint32_t pose_index) {
+  TRACE_EVENT1("gpu", "VrShellGl::DrawFrame", "frame", pose_index);
   // Reset the viewport list to just the pair of viewports for the
   // primary buffer each frame. Head-locked viewports get added by
   // DrawVrShell if needed.
   buffer_viewport_list_->SetToRecommendedBufferViewports();
 
-  gvr::Frame frame = swap_chain_->AcquireFrame();
-  gvr::ClockTimePoint target_time = gvr::GvrApi::GetTimePointNow();
-  target_time.monotonic_system_time_nanos += kPredictionTimeWithoutVsyncNanos;
+  if (web_vr_mode_) {
+    if (!pose_index) {
+      LOG(INFO) << "klausw:DrawFrame: no pose index, not drawing WebVR.";
+      return;
+    }
 
-  gvr::Mat4f head_pose =
-      gvr_api_->GetHeadSpaceFromStartSpaceRotation(target_time);
+    webvr_time_surfaced_[pose_index % kPoseRingBufferSize] = getMonotonicTimestampMs();
 
-  gvr::Vec3f position = GetTranslation(head_pose);
-  if (position.x == 0.0f && position.y == 0.0f && position.z == 0.0f) {
-    // This appears to be a 3DOF pose without a neck model. Add one.
-    // The head pose has redundant data. Assume we're only using the
-    // object_from_reference_matrix, we're not updating position_external.
-    // TODO: Not sure what object_from_reference_matrix is. The new api removed
-    // it. For now, removing it seems working fine.
-    gvr_api_->ApplyNeckModel(head_pose, 1.0f);
+    // If needed, resize the primary buffer for use with WebVR.
+    if (render_size_primary_ != render_size_primary_webvr_) {
+      if (!render_size_primary_webvr_.width) {
+        VLOG(2) << "WebVR rendering size not known yet, dropping frame";
+        return;
+      }
+      VLOG(1) << "WebVR set size " << render_size_primary_webvr_.width << "x" << render_size_primary_webvr_.height;
+      render_size_primary_ = render_size_primary_webvr_;
+      swap_chain_->ResizeBuffer(kFramePrimaryBuffer, render_size_primary_);
+    }
+  } else {
+    if (render_size_primary_ != render_size_primary_vrshell_) {
+      VLOG(1) << "WebVR restore size " << render_size_primary_vrshell_.width << "x" << render_size_primary_vrshell_.height;
+      render_size_primary_ = render_size_primary_vrshell_;
+      swap_chain_->ResizeBuffer(kFramePrimaryBuffer, render_size_primary_);
+    }
+  }
+
+  gvr::Mat4f head_pose;
+  gvr::Frame frame = gvr::Frame(nullptr);
+  {
+    TRACE_EVENT0("gpu", "AcquireFrame");
+    frame = swap_chain_->AcquireFrame();
+  }
+
+  if (web_vr_mode_) {
+    int idx = pose_index % kPoseRingBufferSize;
+    webvr_time_acquired_[idx] = getMonotonicTimestampMs();
+    // TODO(klausw): report acquire time back to JS? If it blocks,
+    // completion time == VSYNC time or a close approximation which
+    // may be useful. But not helpful if it doesn't block.
+    head_pose = webvr_head_pose_[idx];
+  } else {
+    gvr::ClockTimePoint target_time = gvr::GvrApi::GetTimePointNow();
+    target_time.monotonic_system_time_nanos += kPredictionTimeWithoutVsyncNanos;
+
+    head_pose = gvr_api_->GetHeadSpaceFromStartSpaceRotation(target_time);
+
+    gvr::Vec3f position = GetTranslation(head_pose);
+    if (position.x == 0.0f && position.y == 0.0f && position.z == 0.0f) {
+      // This appears to be a 3DOF pose without a neck model. Add one.
+      // The head pose has redundant data. Assume we're only using the
+      // object_from_reference_matrix, we're not updating position_external.
+      // TODO: Not sure what object_from_reference_matrix is. The new api
+      // removed it. For now, removing it seems working fine.
+      gvr_api_->ApplyNeckModel(head_pose, 1.0f);
+    }
   }
 
   frame.BindBuffer(kFramePrimaryBuffer);
@@ -627,45 +694,86 @@ void VrShellGl::DrawFrame() {
   UpdateController(GetForwardVector(head_pose));
 
   if (web_vr_mode_) {
-    DrawWebVr();
-
-    // When using async reprojection, we need to know which pose was used in
-    // the WebVR app for drawing this frame. Due to unknown amounts of
-    // buffering in the compositor and SurfaceTexture, we read the pose number
-    // from a corner pixel. There's no point in doing this for legacy
-    // distortion rendering since that doesn't need a pose, and reading back
-    // pixels is an expensive operation. TODO(klausw,crbug.com/655722): stop
-    // doing this once we have working no-compositor rendering for WebVR.
-    if (gvr_api_->GetAsyncReprojectionEnabled()) {
-      int pose_index_byte = GetPixelEncodedPoseIndexByte();
-      if (WebVrPoseByteIsValid(pose_index_byte)) {
-        // We have a valid pose, use it for reprojection.
-        webvr_left_viewport_->SetReprojection(GVR_REPROJECTION_FULL);
-        webvr_right_viewport_->SetReprojection(GVR_REPROJECTION_FULL);
-        head_pose = webvr_head_pose_[pose_index_byte % kPoseRingBufferSize];
-        // We can't mark the used pose as invalid since unfortunately
-        // we have to reuse them. The compositor will re-submit stale
-        // frames on vsync, and we can't tell that this has happened
-        // until we've read the pose index from it, and at that point
-        // it's too late to skip rendering.
-      } else {
-        // If we don't get a valid frame ID back we shouldn't attempt
-        // to reproject by an invalid matrix, so turn off reprojection
-        // instead. Invalid poses can permanently break reprojection
-        // for this GVR instance: http://crbug.com/667327
-        webvr_left_viewport_->SetReprojection(GVR_REPROJECTION_NONE);
-        webvr_right_viewport_->SetReprojection(GVR_REPROJECTION_NONE);
-      }
+    DrawWebVr(pose_index);
+#define CHECK_FRAME_COUNTER_PIXEL_FOR_DEBUGGING 0
+#if CHECK_FRAME_COUNTER_PIXEL_FOR_DEBUGGING
+    uint32_t pixel_pose = GetPixelEncodedPoseIndex();
+    if (pixel_pose != pose_index) {
+      LOG(ERROR) << __FUNCTION__ << ": poses got out of sync, pixel=" << pixel_pose << " != pose_index=" << pose_index;
     }
+#endif
   }
 
   DrawVrShell(head_pose, frame);
 
   frame.Unbind();
+  glFlush();
   frame.Submit(*buffer_viewport_list_, head_pose);
 
   // No need to SwapBuffers for an offscreen surface.
-  ScheduleNextDrawFrame();
+  // TODO(klausw): is this true? Test with async reprojection off.
+#if 0
+  if (web_vr_mode_ && !gvr_api_->GetAsyncReprojectionEnabled()) {
+    // WebVR uses RENDERMODE_WHEN_DIRTY for the Java glSurfaceView,
+    // and never actually marks frames as dirty. We need to manually
+    // swap buffers if not using reprojection since the GvrLayout
+    // won't do it for us.
+    eglSwapBuffers(eglGetDisplay(EGL_DEFAULT_DISPLAY),
+                   eglGetCurrentSurface(EGL_DRAW));
+  }
+#endif
+
+  if (web_vr_mode_) {
+    double submit_time = webvr_time_submit_[pose_index % kPoseRingBufferSize];
+
+    double prev_submit_time = 0.0;
+    for (int i = 1; i < kPoseRingBufferSize; ++i) {
+      int offset = kPoseRingBufferSize - i;
+      prev_submit_time = webvr_time_submit_[
+          (pose_index + offset) % kPoseRingBufferSize];
+      if (prev_submit_time != 0.0)
+        break;
+    }
+
+    int frameI = 1;
+    if (prev_submit_time != 0.0) {
+      // Rounded integer "frames taken" assuming 60Hz base rate.
+      frameI = ((submit_time - prev_submit_time) * 60 / 1000 + 0.5);
+      if (!frameI) frameI = 1;
+    }
+
+    int idx = pose_index % kPoseRingBufferSize;
+    double frame_start_time = webvr_time_frame_start_[idx];
+    double get_pose_time = webvr_time_get_pose_[idx];
+    double got_pose_time = webvr_time_got_pose_[idx];
+    double surfaced_time = webvr_time_surfaced_[idx];
+    double acquired_time = webvr_time_acquired_[idx];
+    double drawn_time = getMonotonicTimestampMs();
+
+    LOG(INFO) << "timing for frame " << pose_index <<
+        ", frameI " << frameI <<
+        ", rAF " << std::fixed << std::setprecision(1) <<
+        (get_pose_time - frame_start_time) << " getPose " <<
+        (got_pose_time - get_pose_time) << " gotPose " <<
+        (submit_time - got_pose_time) << " submit " <<
+        (surfaced_time - submit_time) << " surfaced " <<
+        (acquired_time - surfaced_time) << " acquired " <<
+        (drawn_time - acquired_time) << " drawn ";
+
+    // TODO(klausw): can completion reporting be moved earlier? I
+    // tried doing so right after AcquireFrame, but then framerate was
+    // very wobbly. Try moving the callback after DrawWebVr +
+    // glFlush() (not finish) to see if that helps?
+    main_thread_task_runner_->PostTask(FROM_HERE, base::Bind(
+        &VrShell::OnWebVRFrameSubmitted, weak_vr_shell_,
+        webvr_surface_handle_,
+        pose_index,
+        acquired_time - submit_time));
+  } else {
+    // Only request a new scheduled frame in non-WebVR mode. In WebVR mode,
+    // the next frame will be drawn in response to SubmitFrame.
+    ScheduleNextDrawFrame();
+  }
 }
 
 void VrShellGl::DrawVrShell(const gvr::Mat4f& head_pose,
@@ -727,11 +835,152 @@ void VrShellGl::DrawVrShell(const gvr::Mat4f& head_pose,
   }
 }
 
-gvr::Sizei VrShellGl::GetWebVRCompositorSurfaceSize() {
-  // This is a stopgap while we're using the WebVR compositor rendering path.
-  // TODO(klausw,crbug.com/655722): Remove this method and member once we're
-  // using a separate WebVR render surface.
-  return content_tex_physical_size_;
+void VrShellGl::GetWebVRSurfaceHandle(int32_t width, int32_t height, const device::mojom::VRDisplay::GetSurfaceHandleCallback& callback) {
+  VLOG(2) << __FUNCTION__ << ": size=" << width << "x" << height;
+
+  if (!webvr_surface_texture_.get()) {
+    // We can't set up a surface due to not having a SurfaceTexture.
+    VLOG(1) << __FUNCTION__ << ": Failed, don't have a SurfaceTexture";
+    callback.Run(0);

[artem.bolgar, 2017/02/14 05:04:24]

You can't do this here. The callback may be executed from the thread, where it
was 'established' ('created', 'bound', 'connected') (not sure what the right
term is). Which is the thread of VrShell, while VrShellGL is a separate thread
here. Doing this here causes an assertion in interface_endpoint_client.cc,
Accept method, task_runner_->RunsTasksOnCurrentThread(). The proper way is to
post another task back to VrShell (main) thread and execute the callback from
there.

+    return;
+  }
+
+  if (webvr_surface_handle_) {
+    // We have a surface, resize if needed.
+    if (render_size_primary_webvr_.width == width && render_size_primary_webvr_.height == height) {
+      VLOG(1) << __FUNCTION__ << ": Ignoring redundant call, this matches the current size.";
+    } else {
+      render_size_primary_webvr_.width = width;
+      render_size_primary_webvr_.height = height;
+      // The size is a bit tricky to change after the fact, see
+      // SurfaceTexture.setDefaultBufferSize documentation:
+      //
+      // For OpenGL ES, the EGLSurface should be destroyed
+      // (via eglDestroySurface), made not-current (via
+      // eglMakeCurrent), and then recreated (via
+      // eglCreateWindowSurface) to ensure that the new
+      // default size has taken effect.
+      webvr_surface_texture_->SetDefaultBufferSize(width, height);
+    }
+  } else {
+    // Create a new surface.
+    render_size_primary_webvr_.width = width;
+    render_size_primary_webvr_.height = height;
+    webvr_surface_texture_->SetDefaultBufferSize(width, height);
+    // Assume we've already created the Surface.
+    //Java_VrShellImpl_createWebVrRenderSurface(env, j_vr_shell_.obj(), width, height);
+    SetWebVrSurface();
+  }
+  callback.Run(webvr_surface_handle_);

[artem.bolgar, 2017/02/14 05:04:24]

You can't do this here. The callback may be executed from the thread, where it
was 'established' ('created', 'bound', 'connected') (not sure what the right
term is). Which is the thread of VrShell, while VrShellGL is a separate thread
here. Doing this here causes an assertion in interface_endpoint_client.cc,
Accept method, task_runner_->RunsTasksOnCurrentThread(). The proper way is to
post another task back to VrShell (main) thread and execute the callback from
there.

+}
+
+void VrShellGl::SetWebVrSurface() {
+  VLOG(1) << __FUNCTION__ << ": size=" << render_size_primary_webvr_.width << "x" << render_size_primary_webvr_.height << " webvr_texture_id_=" << webvr_texture_id_ << " webvr_surface_handle_=" << webvr_surface_handle_;
+
+  if (webvr_surface_handle_) {
+    VLOG(1) << __FUNCTION__ << ": ignoring redundant call, already have webvr_surface_handle_=" << webvr_surface_handle_;
+    return;
+  }
+
+  // Note: This ensures that any local references used by
+  // ANativeWindow_fromSurface are released immediately. This is needed as a
+  // workaround for https://code.google.com/p/android/issues/detail?id=68174
+  JNIEnv* env = base::android::AttachCurrentThread();
+  base::android::ScopedJavaLocalFrame scoped_local_reference_frame(env);
+  ANativeWindow* window = ANativeWindow_fromSurface(
+      env, webvr_surface_->j_surface().obj());
+
+  // This variant doesn't seem to be working - lookup fails?!
+  //ANativeWindow* window = webvr_surface_texture_->CreateSurface();
+
+  gpu::GpuSurfaceTracker* tracker = gpu::GpuSurfaceTracker::Get();
+  ANativeWindow_acquire(window);
+
+  // TODO(klausw): is setBuffersGeometry necessary>
+  ANativeWindow_setBuffersGeometry(window, render_size_primary_webvr_.width, render_size_primary_webvr_.height, WINDOW_FORMAT_RGBA_8888);
+
+  auto handle = tracker->AddSurfaceForNativeWidget(window);
+
+  tracker->RegisterViewSurface(handle, webvr_surface_->j_surface().obj());
+
+  webvr_surface_handle_ = handle;
+
+  // Now we're ready for child_process_service_impl.cc to fetch it via
+  // AIDL/Binder by ID.
+
+  ANativeWindow_release(window);
+
+  VLOG(1) << __FUNCTION__ << ": size=" << render_size_primary_webvr_.width << "x" << render_size_primary_webvr_.height << ", webvr_surface_handle_=" << handle;
+  // TODO(klausw): add cleanup to avoid leaking surfaces:
+  //
+  // The caller must release the underlying reference when done with the handle
+  // by calling ANativeWindow_release().
+}
+
+void VrShellGl::SubmitWebVRFrame(int32_t surface_handle, const device::mojom::VRPosePtr& pose) {
+  // uint32_t pose_index, double frameStart, double serviceStart, double getPose, double gotPose, double submit) {
+  uint32_t pose_index = pose->poseIndex;
+
+  if (surface_handle != webvr_surface_handle_) {
+    VLOG(2) << __FUNCTION__ << ": ignoring submitted frame for surface " << surface_handle << ", ours is " << webvr_surface_handle_;
+  }
+
+  TRACE_EVENT1("media", "klausw:VrShell SubmitWebVRFrame", "frame", pose_index);
+  VLOG(2) << __FUNCTION__ << ": frame " << pose_index;
+
+  webvr_last_submitted_ = pose_index;
+
+  int idx = pose_index % kPoseRingBufferSize;
+  double submit_time = getMonotonicTimestampMs();
+  webvr_time_submit_[idx] = submit_time;
+
+#if 0
+  // Align clocks. TODO(klausw): this assumes submit times being equal, this ignores RPC lag.
+  double submitTs = pose->ts_submit;
+  auto fromJS = [=](double t) { return t - submitTs + submit_time; };
+  webvr_time_frame_start_[idx] = fromJS(pose->ts_frameStart);
+  webvr_time_get_pose_[idx] = fromJS(pose->ts_getPose);
+  webvr_time_got_pose_[idx] = fromJS(pose->ts_gotPose);
+#else
+  webvr_time_frame_start_[idx] = pose->ts_frameStart;
+  webvr_time_get_pose_[idx] = pose->ts_getPose;
+  webvr_time_got_pose_[idx] = pose->ts_gotPose;
+#endif
+
+  //Java_VrShellImpl_expectWebVrFrame(env, j_vr_shell_.obj(), static_cast<jlong>(pose_index));
+  VLOG(1) << __FUNCTION__ << ": expecting WebVR frame " << pose_index;
+  webvr_pending_poses_.push_back(pose_index);
+  if (webvr_already_available_frames_ > 0) {
+    // If the "frame available" was already triggered, draw now.
+    VLOG(2) << __FUNCTION__ << ": Drawing saved frame now";
+    --webvr_already_available_frames_;
+    OnWebVrFrameAvailable();
+  }
+
+  {
+    TRACE_EVENT1("gpu", "glFinish", "before frame", pose_index);
+    // This is a load-bearing glFinish. I'm not entirely sure what's
+    // going on since we haven't actually emitted any GL commands on
+    // this context since the glFlush at the end of the previous
+    // frame, but this measurably reduces stalls in AcquireFrame and
+    // steadies the framerate, at the cost of reducing throughput. It
+    // effectively aligns rAF calls to be in sync with frame
+    // completion.
+    //
+    // Without the glFinish here, rAF calls stay aligned to vsync,
+    // with dropped frames to catch up as needed. This looks jankier.
+    //
+    // Putting the glFinish at the end of vr_shell's DrawFrame causes
+    // a larger latency gap than doing it here.
+    //
+    // TODO(klausw): try adjusting rAF timing offsets to keep timing
+    // steady? Or is it possible to tweak pose prediction to handle
+    // this better? May need cooperation from the JS app to handle
+    // uneven timing.
+    //
+    //if (pose_index % 20 >= 10)
+    glFinish();
+  }
 }
 
 void VrShellGl::DrawUiView(const gvr::Mat4f* head_pose,
@@ -863,8 +1112,8 @@ void VrShellGl::DrawCursor(const gvr::Mat4f& render_matrix) {
   }
 }
 
-void VrShellGl::DrawWebVr() {
-  TRACE_EVENT0("gpu", "VrShellGl::DrawWebVr");
+void VrShellGl::DrawWebVr(uint32_t pose_index) {
+  TRACE_EVENT1("gpu", "VrShellGl::DrawWebVr", "frame", pose_index);
   // Don't need face culling, depth testing, blending, etc. Turn it all off.
   glDisable(GL_CULL_FACE);
   glDepthMask(GL_FALSE);
@@ -876,6 +1125,21 @@ void VrShellGl::DrawWebVr() {
   glViewport(0, 0, render_size_primary_.width, render_size_primary_.height);
   vr_shell_renderer_->GetWebVrRenderer()->Draw(webvr_texture_id_);
 
+  if (!webvr_texture_bounds_need_update_at_.empty()) {
+    uint32_t next_at = webvr_texture_bounds_need_update_at_.front();
+    VLOG(2) << __FUNCTION__ << ": bounds update at " << next_at;
+    if (next_at <= pose_index && pose_index - next_at < 0x40000000) {
+      auto left_bounds = webvr_texture_bounds_left_.front();
+      auto right_bounds = webvr_texture_bounds_right_.front();
+      webvr_texture_bounds_need_update_at_.pop_front();
+      webvr_texture_bounds_left_.pop_front();
+      webvr_texture_bounds_right_.pop_front();
+      VLOG(2) << __FUNCTION__ << ": Update texture bounds, left l=" << left_bounds.left << ",r=" << left_bounds.right << ",t=" << left_bounds.top << ",b=" << left_bounds.bottom;
+      webvr_left_viewport_->SetSourceUv(left_bounds);
+      webvr_right_viewport_->SetSourceUv(right_bounds);
+    }
+  }
+
   buffer_viewport_list_->SetBufferViewport(GVR_LEFT_EYE,
                                            *webvr_left_viewport_);
   buffer_viewport_list_->SetBufferViewport(GVR_RIGHT_EYE,
@@ -897,18 +1161,22 @@ void VrShellGl::OnResume() {
   gvr_api_->RefreshViewerProfile();
   gvr_api_->ResumeTracking();
   controller_->OnResume();
-  draw_task_.Reset(base::Bind(&VrShellGl::DrawFrame, base::Unretained(this)));
+  draw_task_.Reset(base::Bind(&VrShellGl::DrawFrame, base::Unretained(this), 0));
   ScheduleNextDrawFrame();
 }
 
 void VrShellGl::SetWebVrMode(bool enabled) {
+  VLOG(1) << __FUNCTION__ << ": enabled=" << enabled;
   web_vr_mode_ = enabled;
 }
 
-void VrShellGl::UpdateWebVRTextureBounds(const gvr::Rectf& left_bounds,
+void VrShellGl::UpdateWebVRTextureBounds(uint32_t for_pose_index,
+                                         const gvr::Rectf& left_bounds,
                                          const gvr::Rectf& right_bounds) {
-  webvr_left_viewport_->SetSourceUv(left_bounds);
-  webvr_right_viewport_->SetSourceUv(right_bounds);
+  VLOG(2) << __FUNCTION__ << ": for_pose_index=" << for_pose_index << " left_bounds l=" << left_bounds.left << ",r=" << left_bounds.right << ",t=" << left_bounds.top << ",b=" << left_bounds.bottom;
+  webvr_texture_bounds_need_update_at_.push_back(for_pose_index);
+  webvr_texture_bounds_left_.push_back(left_bounds);
+  webvr_texture_bounds_right_.push_back(right_bounds);
 }
 
 gvr::GvrApi* VrShellGl::gvr_api() {