Fix DCHECKs in V4l2VideoDevice.

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 5939c45211e16b939c69c96be2242968144c8385..a2535dfca343032a66e97eb1f1dcd37885674ba2 100644
--- a/media/base/video_frame.h
+++ b/media/base/video_frame.h
@@ -219,6 +219,11 @@ class MEDIA_EXPORT VideoFrame : public base::RefCountedThreadSafe<VideoFrame> {
   // Returns horizontal bits per pixel for given |plane| and |format|.
   static int PlaneHorizontalBitsPerPixel(Format format, size_t plane);
 
+  // Returns the number of bytes per row for the given plane, format, and width.
+  // This refers to the bytes representing frame data scanlines without stride

[Pawel Osciak, 2014/08/18 07:52:03]

We do align the given width though in the impl...

[wuchengli, 2014/08/18 09:09:00]

It refers only to the stride. The original function comments is at line 237.
I'll leave it as is...

[Pawel Osciak, 2014/08/20 10:46:06]

The issue is that it used to not take width, so it returned the result for row
bytes of actual instance of VF.
This method however takes width and aligns it if needed. This is unexpected,
especially since this doc says "without padding". So it suggests width is
unchanged. Please instead say that width may be aligned to format requirements.

[wuchengli, 2014/08/22 05:32:05]

Done.

+  // padding.
+  static int RowBytes(size_t plane, Format format, int width);
+
   Format format() const { return format_; }
 
   const gfx::Size& coded_size() const { return coded_size_; }
@@ -284,6 +289,11 @@ class MEDIA_EXPORT VideoFrame : public base::RefCountedThreadSafe<VideoFrame> {
 
  private:
   friend class base::RefCountedThreadSafe<VideoFrame>;
+
+  // Returns true if |plane| is less than the number of planes for the given
+  // format. This can be used to DCHECK() plane parameters.
+  static bool IsValidPlane(size_t plane, VideoFrame::Format format);
+
   // Clients must use the static CreateFrame() method to create a new frame.
   VideoFrame(Format format,
              const gfx::Size& coded_size,
@@ -296,9 +306,6 @@ class MEDIA_EXPORT VideoFrame : public base::RefCountedThreadSafe<VideoFrame> {
 
   void AllocateYUV();
 
-  // Used to DCHECK() plane parameters.
-  bool IsValidPlane(size_t plane) const;
-
   // Frame format.
   const Format format_;