[Android WebView] Implement Ubercomp for Render Thread support

android_webview/browser/aw_browser_main_parts.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 "android_webview/browser/aw_browser_main_parts.h"
 
 #include "android_webview/browser/aw_browser_context.h"
 #include "android_webview/browser/aw_result_codes.h"
+#include "android_webview/common/aw_switches.h"
 #include "base/android/build_info.h"
 #include "base/android/memory_pressure_listener_android.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/path_service.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/result_codes.h"
 #include "content/public/common/url_utils.h"
@@ skipping 36 matching lines @@
       pak_path.AppendASCII("webviewchromium.pak"),
       ui::SCALE_FACTOR_NONE);
 
   base::android::MemoryPressureListenerAndroid::RegisterSystemCallback(
       base::android::AttachCurrentThread());
 
   return content::RESULT_CODE_NORMAL_EXIT;
 }
 
 void AwBrowserMainParts::PreMainMessageLoopRun() {
-  if (!gpu::gles2::MailboxSynchronizer::Initialize()) {
-    CommandLine::ForCurrentProcess()->AppendSwitch(
-        switches::kDisableAccelerated2dCanvas);
+  // TODO(boliu): Can't support accelerated 2d canvas and WebGL with ubercomp
+  // yet: crbug.com/352424.
+  if (!switches::UbercompEnabled() &&
+      !gpu::gles2::MailboxSynchronizer::Initialize()) {
+    CommandLine* cl = CommandLine::ForCurrentProcess();
+    cl->AppendSwitch(switches::kDisableAccelerated2dCanvas);
+    cl->AppendSwitch(switches::kDisableExperimentalWebGL);
   }
 
   browser_context_->PreMainMessageLoopRun();
   // This is needed for WebView Classic backwards compatibility
   // See crbug.com/298495
   content::SetMaxURLChars(20 * 1024 * 1024);
 }
 
 bool AwBrowserMainParts::MainMessageLoopRun(int* result_code) {
   // Android WebView does not use default MessageLoop. It has its own
   // Android specific MessageLoop.
   return true;
 }
 
 }  // namespace android_webview