Roll WebGL 6a1c97a..582169b

https://chromium.googlesource.com/external/khronosgroup/webgl.git/+log/6a1c97a..582169b

BUG=634525

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/2335113002
Cr-Commit-Position: refs/heads/master@{#418658}

DEPS

@@ -183,7 +183,7 @@ deps = {
     Var('chromium_git') + '/external/bidichecker/lib.git' + '@' + '97f2aa645b74c28c57eca56992235c79850fa9e0',
 
   'src/third_party/webgl/src':
-   Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + '6a1c97ad04302a6ddae7f004a00b47a47f5d0b13',
+   Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + '582169b7e3864a27e50ce0c07c9c346cb267f94c',
 
   'src/third_party/webdriver/pylib':
     Var('chromium_git') + '/external/selenium/py.git' + '@' + '5fd78261a75fe08d27ca4835fb6c5ce4b42275bd',

content/test/gpu/gpu_tests/webgl2_conformance_expectations.py

@@ -159,6 +159,9 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
     # self.Fail('deqp/functional/gles3/fbocompleteness.html',
     #     ['mac', ('nvidia', 0xfe9)], bug=616562)
 
+    self.Fail('conformance2/rendering/blitframebuffer-filter-srgb.html',
+        ['mac'], bug=634525)
+
     self.Fail('deqp/data/gles3/shaders/linkage.html',
         ['mac'], bug=641129)