Revert 255386 "Support ARGB_8888 by default in GLHelperReadbackS..."

trunk/src/content/common/gpu/client/gl_helper_readback_support.cc

 // Copyright 2014 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 "content/common/gpu/client/gl_helper_readback_support.h"
 #include "base/logging.h"
 
 namespace content {
 
 GLHelperReadbackSupport::GLHelperReadbackSupport(gpu::gles2::GLES2Interface* gl)
@@ skipping 19 matching lines @@
 }
 
 void GLHelperReadbackSupport::CheckForReadbackSupport(
     SkBitmap::Config texture_format) {
   bool supports_format = false;
   switch (texture_format) {
     case SkBitmap::kRGB_565_Config:
       supports_format = SupportsFormat(GL_RGB, GL_UNSIGNED_SHORT_5_6_5);
       break;
     case SkBitmap::kARGB_8888_Config:
-      // This is the baseline, assume always true.
-      supports_format = true;
+      supports_format = SupportsFormat(GL_RGBA, GL_UNSIGNED_BYTE);
       break;
     case SkBitmap::kARGB_4444_Config:
       supports_format = false;
       break;
     default:
       NOTREACHED();
       supports_format = false;
       break;
   }
   DCHECK((int)texture_format < (int)SkBitmap::kConfigCount);
@@ skipping 33 matching lines @@
       return true;
     case FORMAT_NOT_SUPPORTED:
       return false;
     default:
       NOTREACHED();
       return false;
   }
 }
 
 }  // namespace content