Query the preferred readback config in CopyFromBackingStore

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 73c306d28292d3d19feb1d8aec5d5d9ba7fa3633..3cd158729be2b8d30a7aed79288d35c037feeb6c 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -718,16 +718,15 @@ void RenderWidgetHostImpl::SetIsLoading(bool is_loading) {
 void RenderWidgetHostImpl::CopyFromBackingStore(
     const gfx::Rect& src_subrect,
     const gfx::Size& accelerated_dst_size,
-    const base::Callback<void(bool, const SkBitmap&)>& callback) {
+    const base::Callback<void(bool, const SkBitmap&)>& callback,
+    const SkBitmap::Config& bitmap_config) {
   if (view_ && is_accelerated_compositing_active_) {
     TRACE_EVENT0("browser",
         "RenderWidgetHostImpl::CopyFromBackingStore::FromCompositingSurface");
     gfx::Rect accelerated_copy_rect = src_subrect.IsEmpty() ?
         gfx::Rect(view_->GetViewBounds().size()) : src_subrect;
-    view_->CopyFromCompositingSurface(accelerated_copy_rect,
-                                      accelerated_dst_size,
-                                      callback,
-                                      SkBitmap::kARGB_8888_Config);
+    view_->CopyFromCompositingSurface(
+        accelerated_copy_rect, accelerated_dst_size, callback, bitmap_config);
     return;
   }
 
@@ -2532,4 +2531,10 @@ void RenderWidgetHostImpl::AddLatencyInfoComponentIds(
   }
 }
 
+SkBitmap::Config RenderWidgetHostImpl::PreferredReadbackFormat() {
+  if (view_)
+    return view_->PreferredReadbackFormat();
+  return SkBitmap::kARGB_8888_Config;
+}
+
 }  // namespace content