gpu: reference target surfaces through a globally unique surface id.

content/browser/renderer_host/render_process_host_impl.cc

Index: content/browser/renderer_host/render_process_host_impl.cc
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index 5e57a26dc19ea094317ad7488ca4cf2863774836..be0265dbe247858e40de1ddfbf73c431116e18bb 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -833,12 +833,6 @@ void RenderProcessHostImpl::ClearTransportDIBCache() {
   cached_dibs_.clear();
 }
 
-void RenderProcessHostImpl::SetCompositingSurface(
-    int render_widget_id,
-    gfx::PluginWindowHandle compositing_surface) {
-  widget_helper_->SetCompositingSurface(render_widget_id, compositing_surface);
-}
-
 bool RenderProcessHostImpl::Send(IPC::Message* msg) {
   if (!channel_.get()) {
     if (!is_initialized_) {