Ensure GL initialization only happens once, and provide common init path

cc/test/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/pixel_test.h"
 
 #include "base/command_line.h"
 #include "base/path_service.h"
 #include "base/run_loop.h"
 #include "cc/base/switches.h"
 #include "cc/output/compositor_frame_metadata.h"
 #include "cc/output/copy_output_request.h"
 #include "cc/output/copy_output_result.h"
 #include "cc/output/gl_renderer.h"
 #include "cc/output/output_surface_client.h"
 #include "cc/output/software_renderer.h"
 #include "cc/resources/resource_provider.h"
 #include "cc/resources/texture_mailbox_deleter.h"
 #include "cc/test/fake_output_surface_client.h"
 #include "cc/test/paths.h"
 #include "cc/test/pixel_test_output_surface.h"
 #include "cc/test/pixel_test_software_output_device.h"
 #include "cc/test/pixel_test_utils.h"
 #include "cc/test/test_in_process_context_provider.h"
 #include "testing/gtest/include/gtest/gtest.h"
-#include "ui/gl/gl_implementation.h"
 
 namespace cc {
 
 PixelTest::PixelTest()
     : device_viewport_size_(gfx::Size(200, 200)),
       disable_picture_quad_image_filtering_(false),
       output_surface_client_(new FakeOutputSurfaceClient) {}
 
 PixelTest::~PixelTest() {}
 
@@ skipping 74 matching lines @@
 
   CommandLine* cmd = CommandLine::ForCurrentProcess();
   if (cmd->HasSwitch(switches::kCCRebaselinePixeltests))
     return WritePNGFile(*result_bitmap_, test_data_dir.Append(ref_file), true);
 
   return MatchesPNGFile(
       *result_bitmap_, test_data_dir.Append(ref_file), comparator);
 }
 
 void PixelTest::SetUpGLRenderer(bool use_skia_gpu_backend) {
-  CHECK(gfx::InitializeStaticGLBindings(gfx::kGLImplementationOSMesaGL));
-
   output_surface_.reset(
       new PixelTestOutputSurface(new TestInProcessContextProvider));
   output_surface_->BindToClient(output_surface_client_.get());
 
   resource_provider_ =
       ResourceProvider::Create(output_surface_.get(), NULL, 0, false, 1);
 
   texture_mailbox_deleter_ = make_scoped_ptr(new TextureMailboxDeleter);
 
   renderer_ = GLRenderer::Create(this,
@@ skipping 32 matching lines @@
   output_surface_.reset(new PixelTestOutputSurface(device.Pass()));
   output_surface_->BindToClient(output_surface_client_.get());
   resource_provider_ =
       ResourceProvider::Create(output_surface_.get(), NULL, 0, false, 1);
   renderer_ = SoftwareRenderer::Create(
       this, &settings_, output_surface_.get(), resource_provider_.get())
                   .PassAs<DirectRenderer>();
 }
 
 }  // namespace cc