Make it possible to run WebGL conformance tests on Android

This patch implements the following changes to make it possible to run
the WebGL conformance test suite on Android:

    1. Copy WebGL test data files to the device.

    2. When running the conformance test, turn on WebGL with the
    --enable-webgl command line flag.

    3. Avoid validating the PCI vendor and device ids for the GPU because
    Android has no such concept.

With these changes, you can run the WebGL conformance test by first
building content_browsertests_apk, removing the WebGL exclusion from 
build/android/pylib/gtest/filter/content_browsertests_disabled and then executing:

    $ build/android/run_browser_tests.py -f WebGLConformanceTest.*

BUG=138226

Review URL: https://chromiumcodereview.appspot.com/14944010

git-svn-id: http://src.chromium.org/svn/trunk/src/build@200298 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/pylib/gtest/test_runner.py

@@ -190,6 +190,7 @@ def _GetDataFilesForTestSuite(test_suite_basename):
         'content/test/data/click-noreferrer-links.html',
         'content/test/data/browser_plugin_focus.html',
         'content/test/data/media',
+        'third_party/webgl_conformance',
     ]
   return []