Roll WebGL b973c09..fa214ea

https://chromium.googlesource.com/external/khronosgroup/webgl.git/+log/b973c09..fa214ea

BUG=654134

TEST=bots

CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.win:win_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2448743002
Cr-Commit-Position: refs/heads/master@{#427252}

DEPS

@@ -186,7 +186,7 @@ deps = {
     Var('chromium_git') + '/external/bidichecker/lib.git' + '@' + '97f2aa645b74c28c57eca56992235c79850fa9e0',
 
   'src/third_party/webgl/src':
-    Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + 'b973c091b0bf7021b53f0635a553ee79011195ec',
+    Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + 'fa214eaac764601810e6fbdb9cd78dc6ccead0a2',
 
   'src/third_party/webdriver/pylib':
     Var('chromium_git') + '/external/selenium/py.git' + '@' + '5fd78261a75fe08d27ca4835fb6c5ce4b42275bd',