Move output surface fallback from cc to embedders

mojo/services/html_viewer/weblayertreeview_impl.cc

Index: mojo/services/html_viewer/weblayertreeview_impl.cc
diff --git a/mojo/services/html_viewer/weblayertreeview_impl.cc b/mojo/services/html_viewer/weblayertreeview_impl.cc
index c0d77b1c401ceac1646f42ef3e61d04ca5855b39..d009f3a8963cce05d43d7f114aa5b77e536d3985 100644
--- a/mojo/services/html_viewer/weblayertreeview_impl.cc
+++ b/mojo/services/html_viewer/weblayertreeview_impl.cc
@@ -97,10 +97,14 @@ void WebLayerTreeViewImpl::ApplyViewportDeltas(
   widget_->applyViewportDeltas(scroll_delta, page_scale, top_controls_delta);
 }
 
-void WebLayerTreeViewImpl::RequestNewOutputSurface(bool fallback) {
+void WebLayerTreeViewImpl::RequestNewOutputSurface() {
   layer_tree_host_->SetOutputSurface(output_surface_.Pass());
 }
 
+void WebLayerTreeViewImpl::DidFailToInitializeOutputSurface() {
+  RequestNewOutputSurface();
+}
+
 void WebLayerTreeViewImpl::DidInitializeOutputSurface() {
 }