Roll WebGL 863cabb..8b636f3

DEPS

 # This file is used to manage the dependencies of the Chromium src repo. It is
 # used by gclient to determine what version of each dependency to check out, and
 # where.
 #
 # For more information, please refer to the official documentation:
 #   https://sites.google.com/a/chromium.org/dev/developers/how-tos/get-the-code
 #
 # When adding a new dependency, please update the top-level .gitignore file
 # to list the dependency's destination directory.
 #
@@ skipping 166 matching lines @@
   'src/chrome/test/data/perf/canvas_bench':
    Var('chromium_git') + '/chromium/canvas_bench.git' + '@' + 'a7b40ea5ae0239517d78845a5fc9b12976bfc732',
 
   'src/chrome/test/data/perf/frame_rate/content':
    Var('chromium_git') + '/chromium/frame_rate/content.git' + '@' + 'c10272c88463efeef6bb19c9ec07c42bc8fe22b9',
 
   'src/third_party/bidichecker':
     Var('chromium_git') + '/external/bidichecker/lib.git' + '@' + '97f2aa645b74c28c57eca56992235c79850fa9e0',
 
   'src/third_party/webgl/src':
-   Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + '863cabbe53447cd4e131ee5bf1979bfe9dcf3016',
+   Var('chromium_git') + '/external/khronosgroup/webgl.git' + '@' + '8b636f38a19fa416217ae9882cf8e199f22e44d5',
 
   'src/third_party/webdriver/pylib':
     Var('chromium_git') + '/external/selenium/py.git' + '@' + '5fd78261a75fe08d27ca4835fb6c5ce4b42275bd',
 
   'src/third_party/libvpx/source/libvpx':
    Var('chromium_git') + '/webm/libvpx.git' + '@' +  '904cb53302dfebee4a0d795ad6ccebdd5da5f542',
 
   'src/third_party/ffmpeg':
    Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + 'beef68513861e11156899b1f763097c31808c418',
 
@@ skipping 655 matching lines @@
     'pattern': '\\.sha1',
     'action': ['python', 'src/third_party/instrumented_libraries/scripts/download_binaries.py'],
   },
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     'name': 'gyp',
     'pattern': '.',
     'action': ['python', 'src/build/gyp_chromium'],
   },
 ]