Cleanup shared memory handling in DesktopCapturer interface.

webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc

Index: webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc b/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc
index 3cf64879f9fa6b6c1b033e4d974301b3c046a768..19079bc78b0726cd869451c56b983eaa2224a280 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc
@@ -12,6 +12,8 @@
 
 #include <assert.h>
 
+#include <utility>
+
 #include "webrtc/modules/desktop_capture/desktop_capture_options.h"
 #include "webrtc/modules/desktop_capture/desktop_frame.h"
 #include "webrtc/modules/desktop_capture/desktop_frame_win.h"
@@ -34,6 +36,22 @@ const UINT DWM_EC_ENABLECOMPOSITION = 1;
 
 const wchar_t kDwmapiLibraryName[] = L"dwmapi.dll";
 
+// SharedMemoryFactory that creates SharedMemory using the deprecated
+// DesktopCapturer::Callback::CreateSharedMemory().
+class CallbackSharedMemoryFactory : public SharedMemoryFactory {
+ public:
+  CallbackSharedMemoryFactory(DesktopCapturer::Callback* callback)
+      : callback_(callback) {}
+  ~CallbackSharedMemoryFactory() override {}
+
+  rtc::scoped_ptr<SharedMemory> CreateSharedMemory(size_t size) override {
+    return rtc_make_scoped_ptr(callback_->CreateSharedMemory(size));
+  }
+
+ private:
+  DesktopCapturer::Callback* callback_;
+};
+
 }  // namespace
 
 ScreenCapturerWinGdi::ScreenCapturerWinGdi(const DesktopCaptureOptions& options)
@@ -70,6 +88,11 @@ ScreenCapturerWinGdi::~ScreenCapturerWinGdi() {
     FreeLibrary(dwmapi_library_);
 }
 
+void ScreenCapturerWinGdi::SetSharedMemoryFactory(
+    rtc::scoped_ptr<SharedMemoryFactory> shared_memory_factory) {
+  shared_memory_factory_ = std::move(shared_memory_factory);
+}
+
 void ScreenCapturerWinGdi::Capture(const DesktopRegion& region) {
   TickTime capture_start_time = TickTime::Now();
 
@@ -148,6 +171,8 @@ void ScreenCapturerWinGdi::Start(Callback* callback) {
   assert(callback);
 
   callback_ = callback;
+  if (!shared_memory_factory_)
+    shared_memory_factory_.reset(new CallbackSharedMemoryFactory(callback));
 
   // Vote to disable Aero composited desktop effects while capturing. Windows
   // will restore Aero automatically if the process exits. This has no effect
@@ -237,12 +262,8 @@ bool ScreenCapturerWinGdi::CaptureImage() {
     assert(desktop_dc_ != NULL);
     assert(memory_dc_ != NULL);
 
-    size_t buffer_size = size.width() * size.height() *
-        DesktopFrame::kBytesPerPixel;
-    SharedMemory* shared_memory = callback_->CreateSharedMemory(buffer_size);
-
-    rtc::scoped_ptr<DesktopFrame> buffer(
-        DesktopFrameWin::Create(size, shared_memory, desktop_dc_));
+    rtc::scoped_ptr<DesktopFrame> buffer(DesktopFrameWin::Create(
+        size, shared_memory_factory_.get(), desktop_dc_));
     if (!buffer.get())
       return false;
     queue_.ReplaceCurrentFrame(buffer.release());