Update from https://crrev.com/309415

cc/layers/ui_resource_layer.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/ui_resource_layer.h"
 
 #include "cc/layers/ui_resource_layer_impl.h"
 #include "cc/resources/prioritized_resource.h"
 #include "cc/resources/resource_update.h"
 #include "cc/resources/resource_update_queue.h"
@@ skipping 116 matching lines @@
     ui_resource_holder_ = nullptr;
   }
   UpdateDrawsContent(HasDrawableContent());
   SetNeedsCommit();
 }
 
 void UIResourceLayer::SetUIResourceId(UIResourceId resource_id) {
   if (ui_resource_holder_ && ui_resource_holder_->id() == resource_id)
     return;
 
+  if (!bitmap_.isNull())
+    bitmap_.reset();
+
   if (resource_id)
     ui_resource_holder_ = SharedUIResourceHolder::Create(resource_id);
   else
     ui_resource_holder_ = nullptr;
 
   UpdateDrawsContent(HasDrawableContent());
   SetNeedsCommit();
 }
 
 bool UIResourceLayer::HasDrawableContent() const {
@@ skipping 13 matching lines @@
     gfx::Size image_size =
         layer_tree_host()->GetUIResourceSize(ui_resource_holder_->id());
     layer_impl->SetUIResourceId(ui_resource_holder_->id());
     layer_impl->SetImageBounds(image_size);
     layer_impl->SetUV(uv_top_left_, uv_bottom_right_);
     layer_impl->SetVertexOpacity(vertex_opacity_);
   }
 }
 
 }  // namespace cc