Mozart: Directly associate the renderer with the view tree.

services/gfx/compositor/backend/gpu_rasterizer.cc

 // Copyright 2015 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 "services/gfx/compositor/backend/gpu_rasterizer.h"
 
 #ifndef GL_GLEXT_PROTOTYPES
 #define GL_GLEXT_PROTOTYPES
 #endif
 
@@ skipping 162 matching lines @@
   DCHECK(frame_);
 
   gl_context_->MakeCurrent();
 
   // Update the viewport.
   const SkRect& viewport = frame_->viewport();
   bool stale_surface = false;
   if (!ganesh_surface_ ||
       ganesh_surface_->surface()->width() != viewport.width() ||
       ganesh_surface_->surface()->height() != viewport.height()) {
+    glResizeCHROMIUM(viewport.width(), viewport.height(), 1.0f);
     glViewport(viewport.x(), viewport.y(), viewport.width(), viewport.height());
-    glResizeCHROMIUM(viewport.width(), viewport.height(), 1.0f);
     stale_surface = true;
   }
 
   // Paint the frame.
   {
     mojo::skia::GaneshContext::Scope ganesh_scope(ganesh_context_.get());
 
     if (stale_surface)
       ganesh_surface_.reset(
           new mojo::skia::GaneshFramebufferSurface(ganesh_scope));
 
     frame_->Paint(ganesh_surface_->canvas());
   }
 
   // Swap buffers and listen for completion.
   // TODO: Investigate using |MGLSignalSyncPoint| to wait for completion.
   MGLSwapBuffers();
   frame_callback_.Run(true);
   frame_callback_.Reset();
 }
 
 void GpuRasterizer::PostErrorCallback() {
   task_runner_->PostTask(FROM_HERE, error_callback_);
 }
 
 }  // namespace compositor