Roll WebGL b1aed3a..b973c09

https://chromium.googlesource.com/external/khronosgroup/webgl.git/+log/b1aed3a..b973c09

BUG=656889
TEST=bots
NOTRY=true
TBR=kbr@chromium.org
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://chromiumcodereview.appspot.com/2433323007
Cr-Commit-Position: refs/heads/master@{#426937}

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' + '@' + 'b1aed3a192c338b9c6c1790dbcb3d597a532bc2c',
+    Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + 'b973c091b0bf7021b53f0635a553ee79011195ec',
 
   'src/third_party/webdriver/pylib':
     Var('chromium_git') + '/external/selenium/py.git' + '@' + '5fd78261a75fe08d27ca4835fb6c5ce4b42275bd',

content/test/gpu/gpu_tests/webgl2_conformance_expectations.py

@@ -57,6 +57,8 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
     # All platforms.
     self.Fail('conformance/glsl/bugs/samplers-in-ternary-operator.html',
         bug=657853)
+    self.Fail('conformance2/textures/misc/tex-image-with-bad-args.html',
+        bug=656889)
     self.Fail('conformance2/glsl3/uniform-block-layouts.html',
         bug=657859)
     self.Fail('conformance2/context/methods-2.html', bug=616554)