Start disabling GYP by default in runhooks in some configurations.

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 839 matching lines @@
     # Pull sanitizer-instrumented third-party libraries if requested via
     # GYP_DEFINES.
     'name': 'instrumented_libraries',
     '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'],
+    'action': ['python', 'src/build/gyp_chromium', '--running-as-hook'],
   },
 ]