Expose locks for CopyFromCompositingSurface/CopyFromBackingStore API

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 b4f54df750ac098098d8c0025a0a7bcc2b234e12..6fc4fd0c780565a0fdfadd4759ad69cba60b7cf1 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -747,6 +747,22 @@ void RenderWidgetHostImpl::CopyFromBackingStore(
   callback.Run(result, output.GetBitmap());
 }
 
+bool RenderWidgetHostImpl::CanCopyFromBackingStore() {
+  if (view_)
+    return view_->IsSurfaceAvailableForCopy();
+  return false;
+}
+
+void RenderWidgetHostImpl::LockForCopyFromBackingStore() {
+  if (view_)
+    view_->LockSurfaceForCopy();
+}
+
+void RenderWidgetHostImpl::UnlockForCopyFromBackingStore() {
+  if (view_)
+    view_->UnlockSurfaceForCopy();
+}
+
 #if defined(TOOLKIT_GTK)
 bool RenderWidgetHostImpl::CopyFromBackingStoreToGtkWindow(
     const gfx::Rect& dest_rect, GdkWindow* target) {