Use a mocked compositor for unit tests

chrome/browser/gpu_browsertest.cc

Index: chrome/browser/gpu_browsertest.cc
diff --git a/chrome/browser/gpu_browsertest.cc b/chrome/browser/gpu_browsertest.cc
index 333e78310b5891d0ae783606e3c7e4ddffedd9e2..9a4e853cfbd3014ae13474ccd54e3bd1c16b943b 100644
--- a/chrome/browser/gpu_browsertest.cc
+++ b/chrome/browser/gpu_browsertest.cc
@@ -11,12 +11,10 @@
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/base/in_process_browser_test.h"
-#include "chrome/test/base/test_launcher_utils.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/net_util.h"
-#include "ui/gfx/gl/gl_implementation.h"
 
 class GPUBrowserTest : public InProcessBrowserTest {
  protected:
@@ -33,10 +31,6 @@ class GPUBrowserTest : public InProcessBrowserTest {
   virtual void SetUpCommandLine(CommandLine* command_line) {
     InProcessBrowserTest::SetUpCommandLine(command_line);
 
-    EXPECT_TRUE(test_launcher_utils::OverrideGLImplementation(
-        command_line,
-        gfx::kGLImplementationOSMesaName));
-
     command_line->AppendSwitch(switches::kDisablePopupBlocking);
 
 #if defined(OS_MACOSX)