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..9ad9a3d937229756340ac5d0371a9dac832cd81c 100644
--- a/media/base/video_frame.h
+++ b/media/base/video_frame.h
@@ -219,6 +219,10 @@ 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.
+  // The width may be aligned to format requirements.
+  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 +288,11 @@ class MEDIA_EXPORT VideoFrame : public base::RefCountedThreadSafe<VideoFrame> {
 
  private:
   friend class base::RefCountedThreadSafe<VideoFrame>;
+
+  // Returns true if |plane| is a valid plane number 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 +305,6 @@ 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_;