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

chrome/test/ppapi/ppapi_test.cc

 // Copyright (c) 2012 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 "chrome/test/ppapi/ppapi_test.h"
 
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "base/strings/string_util.h"
@@ skipping 111 matching lines @@
     delegate->Accept();
   else
     delegate->Cancel();
 
   infobar_service->RemoveInfoBar(infobar);
 }
 
 PPAPITestBase::PPAPITestBase() {
 }
 
+void PPAPITestBase::SetUp() {
+  // Some of these tests require pixel output.
+  UseRealGLContexts();
+
+  InProcessBrowserTest::SetUp();
+}
+
 void PPAPITestBase::SetUpCommandLine(CommandLine* command_line) {
   // The test sends us the result via a cookie.
   command_line->AppendSwitch(switches::kEnableFileCookies);
 
   // Some stuff is hung off of the testing interface which is not enabled
   // by default.
   command_line->AppendSwitch(switches::kEnablePepperTesting);
 
   // Smooth scrolling confuses the scrollbar test.
   command_line->AppendSwitch(switches::kDisableSmoothScrolling);
@@ skipping 266 matching lines @@
     const std::string& base,
     const std::string& test_case) {
   return base::StringPrintf("%smode=nacl_newlib&testcase=%s", base.c_str(),
                             test_case.c_str());
 }
 
 void PPAPIBrokerInfoBarTest::SetUpOnMainThread() {
   // The default content setting for the PPAPI broker is ASK. We purposefully
   // don't call PPAPITestBase::SetUpOnMainThread() to keep it that way.
 }