android: Enable WebGL if context robustess extension is supported

If the GL implementation supports the context robustness extension
(GL_{ARB,EXT}_robustness) and promises to tell us about GPU resets, turn
on support for WebGL.

This patch also removes the Android-only --enable-webgl command line
flag. From now on, WebGL support can be forced on with the
--ignore-gpu-blacklist flag.

BUG=112928
NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/21564006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@215135 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 2f997ba..55a147c 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -418,26 +418,11 @@
     SINGLE_VALUE_TYPE(switches::kDisableGpuVsync)
   },
   {
-    "enable-webgl",
-    IDS_FLAGS_ENABLE_WEBGL_NAME,
-    IDS_FLAGS_ENABLE_WEBGL_DESCRIPTION,
-    kOsAndroid,
-#if defined(OS_ANDROID)
-    SINGLE_VALUE_TYPE(switches::kEnableExperimentalWebGL)
-#else
-    SINGLE_VALUE_TYPE("")
-#endif
-  },
-  {
     "disable-webgl",
     IDS_FLAGS_DISABLE_WEBGL_NAME,
     IDS_FLAGS_DISABLE_WEBGL_DESCRIPTION,
-    kOsDesktop,
-#if defined(OS_ANDROID)
-    SINGLE_VALUE_TYPE("")
-#else
+    kOsAll,
     SINGLE_VALUE_TYPE(switches::kDisableExperimentalWebGL)
-#endif
   },
   {
     "disable-webrtc",