Use GLHelper support to validate format before processing texture.

content/browser/compositor/delegated_frame_host.cc

Index: content/browser/compositor/delegated_frame_host.cc
diff --git a/content/browser/compositor/delegated_frame_host.cc b/content/browser/compositor/delegated_frame_host.cc
index e09c38ebc6589ccc1ec5a9ef82e6bc7703ce974a..bc48b335cf334752287000460af88f7ed7dd4f46 100644
--- a/content/browser/compositor/delegated_frame_host.cc
+++ b/content/browser/compositor/delegated_frame_host.cc
@@ -611,6 +611,17 @@ static void CopyFromCompositingSurfaceFinished(
                result ? content::READBACK_SUCCESS : content::READBACK_FAILED);
 }
 
+//// static

[danakj, 2015/01/06 16:16:19]

just one // is enough

[sivag, 2015/01/07 09:33:32]

Done.

+bool DelegatedFrameHost::IsReadbackConfigSupported(SkColorType color_type) {
+  ImageTransportFactory* factory = ImageTransportFactory::GetInstance();
+  GLHelper* gl_helper = factory->GetGLHelper();
+  if (!gl_helper)
+    return false;
+  if (!gl_helper->IsReadbackConfigSupported(color_type))
+    return false;
+  return true;
+}
+
 // static
 void DelegatedFrameHost::PrepareTextureCopyOutputResult(
     const gfx::Size& dst_size_in_pixel,
@@ -618,12 +629,13 @@ void DelegatedFrameHost::PrepareTextureCopyOutputResult(
     ReadbackRequestCallback& callback,
     scoped_ptr<cc::CopyOutputResult> result) {
   DCHECK(result->HasTexture());
+
+  if (!IsReadbackConfigSupported(color_type))

[danakj, 2015/01/06 16:16:19]

This makes us GetGLHelper() twice, IWBN to only call that function once.

Also previously if GetGLHelper() gave null, we would READBACK_FAILED. Now we
READBACK_FORMAT_NOT_SUPPORTED, which maybe is not right?

[sivag, 2015/01/07 09:33:32]

Done.

+    callback.Run(SkBitmap(), content::READBACK_FORMAT_NOT_SUPPORTED);
+
   base::ScopedClosureRunner scoped_callback_runner(
       base::Bind(callback, SkBitmap(), content::READBACK_FAILED));
 
-  // TODO(sikugu): We should be able to validate the format here using
-  // GLHelper::IsReadbackConfigSupported before we processs the result.
-  // See crbug.com/415682.
   scoped_ptr<SkBitmap> bitmap(new SkBitmap);
   if (!bitmap->tryAllocPixels(SkImageInfo::Make(dst_size_in_pixel.width(),
                                                 dst_size_in_pixel.height(),