Remove FORMAT_RGB from gfx::PngCodec

media/gpu/rendering_helper.h

Index: media/gpu/rendering_helper.h
diff --git a/media/gpu/rendering_helper.h b/media/gpu/rendering_helper.h
index 03c15be9b8dc57618ba71bb5a5b39213a9293f01..54dcbed0af7dec8ae3e59a9076940271f4114f00 100644
--- a/media/gpu/rendering_helper.h
+++ b/media/gpu/rendering_helper.h
@@ -139,11 +139,9 @@ class RenderingHelper {
   // Get the GL context.
   gl::GLContext* GetGLContext();
 
-  // Get rendered thumbnails as RGB.
-  // Sets alpha_solid to true if the alpha channel is entirely 0xff.
-  void GetThumbnailsAsRGB(std::vector<unsigned char>* rgb,
-                          bool* alpha_solid,
-                          base::WaitableEvent* done);
+  // Get rendered thumbnails as RGBA.
+  void GetThumbnailsAsRGBA(std::vector<unsigned char>* rgba,
+                           base::WaitableEvent* done);
 
  private:
   struct RenderedVideo {