Defer compositor context creation to the thread.

cc/test/layer_tree_pixel_test.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/test/layer_tree_pixel_test.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/command_line.h"
@@ skipping 36 matching lines @@
       std::unique_ptr<PixelTestSoftwareOutputDevice> software_output_device(
           new PixelTestSoftwareOutputDevice);
       software_output_device->set_surface_expansion_size(
           surface_expansion_size);
       output_surface = base::WrapUnique(new PixelTestOutputSurface(
           std::move(software_output_device), nullptr));
       break;
     }
     case PIXEL_TEST_GL: {
       bool flipped_output_surface = false;
-      scoped_refptr<TestInProcessContextProvider> compositor(
+      scoped_refptr<TestInProcessContextProvider> worker(
           new TestInProcessContextProvider(nullptr));
-      scoped_refptr<TestInProcessContextProvider> worker(
-          new TestInProcessContextProvider(compositor.get()));
+      std::unique_ptr<TestInProcessContextProvider::Factory> compositor(
+          new TestInProcessContextProvider::Factory(worker.get()));
       output_surface = base::WrapUnique(
           new PixelTestOutputSurface(std::move(compositor), std::move(worker),
                                      flipped_output_surface, nullptr));
       break;
     }
   }
 
   output_surface->set_surface_expansion_size(surface_expansion_size);
   return std::move(output_surface);
 }
@@ skipping 205 matching lines @@
 }
 
 void LayerTreePixelTest::Finish() {
   std::unique_ptr<gpu::GLInProcessContext> context =
       CreateTestInProcessContext();
   GLES2Interface* gl = context->GetImplementation();
   gl->Finish();
 }
 
 }  // namespace cc