remove unnecessary Shell::Initialize causing DCHECK on gpu_win bots

It's already called in ShellBrowserMainParts::PreMainMessageLoopRun
which happens earlier.

R=piman@chromium.org
BUG=292874

Review URL: https://chromiumcodereview.appspot.com/23619061

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@223553 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/gpu/gpu_functional_browsertest.cc

@@ -70,7 +70,6 @@ class GpuFunctionalTest : public ContentBrowserTest {
   }
 
   void VerifyGPUProcessOnPage(std::string filename, bool wait) {
-    Shell::Initialize();
     ASSERT_TRUE(test_server()->Start());
     DOMMessageQueue message_queue;