Replace av_malloc with AlignedAlloc for memory allocation in VideoFrame.

media/base/video_frame.h

Index: media/base/video_frame.h
diff --git a/media/base/video_frame.h b/media/base/video_frame.h
index 09e6b43baae128792d8827c12e527b935815d28f..3483e9191a91307ebb9bb8253f8fb3becac3ed09 100644
--- a/media/base/video_frame.h
+++ b/media/base/video_frame.h
@@ -16,6 +16,12 @@ namespace media {
 class MEDIA_EXPORT VideoFrame : public base::RefCountedThreadSafe<VideoFrame> {
  public:
   enum {
+    kFrameSizeAlignment = 16,
+    kFrameSizePadding = 16,
+    kFrameAddressAlignment = 32
+  };
+
+  enum {
     kMaxPlanes = 3,
 
     kRGBPlane = 0,