Use stub GL draw/clear calls for browser tests that do not need pixels.

chrome/browser/extensions/api/tab_capture/tab_capture_performancetest.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 "base/basictypes.h"
 #include "base/command_line.h"
 #if defined(OS_MACOSX)
 #include "base/mac/mac_util.h"
 #endif
 #include "base/strings/stringprintf.h"
@@ skipping 81 matching lines @@
       suffix += "_novsync";
     if (HasFlag(kTestThroughWebRTC))
       suffix += "_webrtc";
     if (!ScalingMethod().empty())
       suffix += "_scale" + ScalingMethod();
     if (HasFlag(kSmallWindow))
       suffix += "_small";
     return suffix;
   }
 
+  virtual void SetUp() OVERRIDE {
+    // These tests needs pixel results.
+    UseRealGLContexts();
+    ExtensionApiTest::SetUp();
+  }
+
   virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
     if (!ScalingMethod().empty()) {
       command_line->AppendSwitchASCII(switches::kTabCaptureUpscaleQuality,
                                       ScalingMethod());
       command_line->AppendSwitchASCII(switches::kTabCaptureDownscaleQuality,
                                       ScalingMethod());
     }
 
     // UI tests boot up render views starting from about:blank. This causes
     // the renderer to start up thinking it cannot use the GPU. To work
     // around that, and allow the frame rate test to use the GPU, we must
     // pass kAllowWebUICompositing.
     command_line->AppendSwitch(switches::kAllowWebUICompositing);
 
     // Some of the tests may launch http requests through JSON or AJAX
     // which causes a security error (cross domain request) when the page
     // is loaded from the local file system ( file:// ). The following switch
     // fixes that error.
     command_line->AppendSwitch(switches::kAllowFileAccessFromFiles);
 
     if (HasFlag(kSmallWindow)) {
       command_line->AppendSwitchASCII(switches::kWindowSize, "800,600");
     } else {
       command_line->AppendSwitchASCII(switches::kWindowSize, "2000,1500");
     }
 
-    UseRealGLContexts();
-
     if (!HasFlag(kUseGpu)) {
       command_line->AppendSwitch(switches::kDisableGpu);
     } else {
       command_line->AppendSwitch(switches::kForceCompositingMode);
     }
 
     if (HasFlag(kDisableVsync))
       command_line->AppendSwitch(switches::kDisableGpuVsync);
 
     command_line->AppendSwitchASCII(switches::kWhitelistedExtensionID,
@@ skipping 119 matching lines @@
     TabCapturePerformanceTest,
     testing::Values(
         kScalingTestBase | kScaleQualityFast,
         kScalingTestBase | kScaleQualityGood,
         kScalingTestBase | kScaleQualityBest,
         kScalingTestBase | kScaleQualityFast | kSmallWindow,
         kScalingTestBase | kScaleQualityGood | kSmallWindow,
         kScalingTestBase | kScaleQualityBest | kSmallWindow));
 
 #endif  // USE_AURA