Allow WebExternalTextureLayerClient to work with mailboxes.

webkit/plugins/ppapi/ppapi_plugin_instance.cc

Index: webkit/plugins/ppapi/ppapi_plugin_instance.cc
diff --git a/webkit/plugins/ppapi/ppapi_plugin_instance.cc b/webkit/plugins/ppapi/ppapi_plugin_instance.cc
index 886338b1f4b286fd204d2506ad1158c02994daa5..3b6a6758e32efb1e408bcb0a35bf8e414eb47cbb 100644
--- a/webkit/plugins/ppapi/ppapi_plugin_instance.cc
+++ b/webkit/plugins/ppapi/ppapi_plugin_instance.cc
@@ -1716,7 +1716,7 @@ void PluginInstance::UpdateLayer() {
   }
   if (want_layer) {
     DCHECK(bound_graphics_3d_.get());
-    texture_layer_ = cc::TextureLayer::Create(this);
+    texture_layer_ = cc::TextureLayer::Create(this, false);
     web_layer_.reset(new WebKit::WebLayerImpl(texture_layer_));
     if (fullscreen_container_)
       fullscreen_container_->SetLayer(web_layer_.get());
@@ -2089,6 +2089,10 @@ WebKit::WebGraphicsContext3D* PluginInstance::context() {
   return bound_graphics_3d_->platform_context()->GetParentContext();
 }
 
+bool PluginInstance::prepareTextureMailbox(cc::TextureMailbox*) {
+  return false;
+}
+
 void PluginInstance::NumberOfFindResultsChanged(PP_Instance instance,
                                                 int32_t total,
                                                 PP_Bool final_result) {