Add a flag to not start GPU process on browser startup

chrome/android/java/src/org/chromium/chrome/browser/init/EmptyBrowserParts.java

 // Copyright 2015 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.
 
 package org.chromium.chrome.browser.init;
 
 /**
  * Empty implementation of the browser parts for easy extension.
  */
 public class EmptyBrowserParts implements BrowserParts {
@@ skipping 32 matching lines @@
 
     @Override
     public boolean isActivityDestroyed() {
         return false;
     }
 
     @Override
     public boolean isActivityFinishing() {
         return false;
     }
+
+    @Override
+    public boolean shouldStartGpuProcess() {
+        return true;
+    }
 }