New method CreateScaledFrame in the VideoFrameFactory interface.

webrtc/media/base/videoframefactory.cc

Index: webrtc/media/base/videoframefactory.cc
diff --git a/webrtc/media/base/videoframefactory.cc b/webrtc/media/base/videoframefactory.cc
index 23925bda56abefb096d71250f0531878478fc532..74332f175cc034bc5ac736e0bed7ad66db60ca72 100644
--- a/webrtc/media/base/videoframefactory.cc
+++ b/webrtc/media/base/videoframefactory.cc
@@ -15,6 +15,54 @@
 
 namespace cricket {
 
+std::unique_ptr<VideoFrame> VideoFrameFactory::CreateScaledFrame(
+    const CapturedFrame* input_frame,
+    int dst_width,
+    int dst_height) const {
+  // Size of the used portion of the input frame.
+  int crop_width = input_frame->width;
+  int crop_height = input_frame->height;
+
+  // Cropp the input frame, if needed to preserve aspect ratio.
+  long aspect_diff = static_cast<long>(crop_width) * dst_height -
+                     static_cast<long>(crop_height) * dst_width;
+  if (aspect_diff > 0) {
+    // Horizontal crop.
+
+    // TODO(nisse): Old code carried a comment saying that MJPG can

[perkj_webrtc, 2016/05/16 06:48:47]

You can add a DCHECK here if you want to check that input_frame is not MJPG. But
we don't support MJPG at this level anymore anyway, MGJP has already been
supported to I420 before reaching libjingle. 

+    // only be cropped vertically, and disabled horizontal cropping in
+    // that case. Still needed?
+    crop_width -= aspect_diff / dst_height;
+    RTC_DCHECK(crop_width > 0);
+  } else if (aspect_diff < 0) {
+    // Vertical crop.
+    crop_height -= (-aspect_diff) / dst_width;
+    RTC_DCHECK(crop_height > 0);
+  }
+  return CreateCroppedAndScaledFrame(
+      input_frame,
+      (input_frame->width - crop_width) / 2,
+      (input_frame->height - crop_height) / 2,
+      crop_width, crop_height,
+      dst_width, dst_height);
+}
+
+// For backwards compatibility, default implementation in terms of old
+// methods. Ignores the position of the cropping window, and leaves it
+// up to CreateAliasedFrame.
+// TODO(nisse): Delete when Chrome's subclass is updated.
+std::unique_ptr<VideoFrame> VideoFrameFactory::CreateCroppedAndScaledFrame(
+    const CapturedFrame* input_frame,
+    int crop_x,
+    int crop_y,
+    int crop_width,
+    int crop_height,
+    int dst_width,
+    int dst_height) const {
+  return std::unique_ptr<VideoFrame>(CreateAliasedFrame(
+      input_frame, crop_width, crop_height, dst_width, dst_height));
+}
+
 VideoFrame* VideoFrameFactory::CreateAliasedFrame(
     const CapturedFrame* input_frame,
     int cropped_input_width,