Ensure GL initialization only happens once, and provide common init path

ui/gl/gl_implementation_android.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 "base/base_paths.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/native_library.h"
 #include "base/path_service.h"
@@ skipping 34 matching lines @@
 }  // namespace
 
 void GetAllowedGLImplementations(std::vector<GLImplementation>* impls) {
   impls->push_back(kGLImplementationEGLGLES2);
 }
 
 bool InitializeStaticGLBindings(GLImplementation implementation) {
   // Prevent reinitialization with a different implementation. Once the gpu
   // unit tests have initialized with kGLImplementationMock, we don't want to
   // later switch to another GL implementation.
-  if (GetGLImplementation() != kGLImplementationNone)
-    return true;
+  DCHECK_EQ(kGLImplementationNone, GetGLImplementation());
 
   switch (implementation) {
     case kGLImplementationEGLGLES2: {
       base::NativeLibrary gles_library = LoadLibrary("libGLESv2.so");
       if (!gles_library)
         return false;
       base::NativeLibrary egl_library = LoadLibrary("libEGL.so");
       if (!egl_library) {
         base::UnloadNativeLibrary(gles_library);
         return false;
@@ skipping 77 matching lines @@
   switch (GetGLImplementation()) {
     case kGLImplementationEGLGLES2:
       return GetGLWindowSystemBindingInfoEGL(info);
     default:
       return false;
   }
   return false;
 }
 
 }  // namespace gfx