Re-Fix DOM exception on GPU pixel browser test.
Re-Fix DOM exception on GPU pixel browser test.

After r94232, the test still failed with "Uncaught Error: SECURITY_ERR: DOM
Exception 18." Now it should not.

BUG=89964
TEST=gpu_tests --gtest_filter=GpuPixelBrowserTest.WebGLTeapot


Review URL: http://codereview.chromium.org/7532021

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@94634 0039d316-1c4b-4281-b951-d872f2087c98

adobe/chromium,adobe/chromium,ropik/chromium,ropik/chromium,gavinp/chromium,ropik/chromium,adobe/chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,ropik/chromium,adobe/chromium,gavinp/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,yitian134/chromium,gavinp/chromium,yitian134/chromium,yitian134/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,yitian134/chromium