Don't set accelerated compositing to true in WebView. It's already defaulted to true.

content/renderer/render_view_impl.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 "content/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/auto_reset.h"
@@ skipping 1027 matching lines @@
 
   // Enable WebGL errors to the JS console if requested.
   settings->setWebGLErrorsToConsoleEnabled(
       prefs.webgl_errors_to_console_enabled);
 
   // Uses the mock theme engine for scrollbars.
   settings->setMockScrollbarsEnabled(prefs.mock_scrollbars_enabled);
 
   settings->setLayerSquashingEnabled(prefs.layer_squashing_enabled);
 
-  // Enable gpu-accelerated compositing always.
-  settings->setAcceleratedCompositingEnabled(true);

[jamesr, 2014/07/22 01:05:04]

for the record,
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...
sets this to true by default

-
   // Enable gpu-accelerated 2d canvas if requested on the command line.
   settings->setAccelerated2dCanvasEnabled(prefs.accelerated_2d_canvas_enabled);
 
   settings->setMinimumAccelerated2dCanvasSize(
       prefs.minimum_accelerated_2d_canvas_size);
 
   // Disable antialiasing for 2d canvas if requested on the command line.
   settings->setAntialiased2dCanvasEnabled(
       !prefs.antialiased_2d_canvas_disabled);
 
@@ skipping 3226 matching lines @@
     std::vector<gfx::Size> sizes;
     ConvertToFaviconSizes(icon_urls[i].sizes(), &sizes);
     if (!url.isEmpty())
       urls.push_back(
           FaviconURL(url, ToFaviconType(icon_urls[i].iconType()), sizes));
   }
   SendUpdateFaviconURL(urls);
 }
 
 }  // namespace content