Revert of [gn] Switch off gyp in runhooks by default (patchset #2 id:20001 of...

Revert of [gn] Switch off gyp in runhooks by default (patchset #2 id:20001 of https://codereview.chromium.org/2327033002/ )

Reason for revert:
Broke stuff - need to fix the argument

Original issue's description:
> [gn] Switch off gyp in runhooks by default
>
> This will be synced with an announcement on v8-dev. This
> doesn't affect directly calling gyp in our old Makefiles.
>
> BUG=chromium:474921
> NOTRY=true
>
> Committed: https://crrev.com/94f813e8dcd4ed5a67cede8af0f949009beaa501
> Cr-Commit-Position: refs/heads/master@{#39308}

TBR=jochen@chromium.org,jkummerow@chromium.org,vogelheim@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:474921

Review-Url: https://codereview.chromium.org/2324173002
Cr-Commit-Position: refs/heads/master@{#39309}

DEPS

@@ -279,6 +279,6 @@ hooks = [
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     "pattern": ".",
-    "action": ["python", "v8/gypfiles/gyp_v8", "--running-as-hook"],
+    "action": ["python", "v8/gypfiles/gyp_v8"],
   },
 ]

gypfiles/gyp_v8

@@ -118,19 +118,10 @@ def run_gyp(args):
 if __name__ == '__main__':
   args = sys.argv[1:]
 
-  gyp_chromium_no_action = os.environ.get('GYP_CHROMIUM_NO_ACTION')
-  if gyp_chromium_no_action == '1':
+  if int(os.environ.get('GYP_CHROMIUM_NO_ACTION', 0)):
     print 'Skipping gyp_v8 due to GYP_CHROMIUM_NO_ACTION env var.'
     sys.exit(0)
 
-  running_as_hook = '--running-as-hook'
-  if running_as_hook in args and gyp_chromium_no_action != '0':
-    print 'GYP is now disabled by default in runhooks.\n'
-    print 'If you really want to run this, either run '
-    print '`python gypfiles/gyp_v8` explicitly by hand '
-    print 'or set the environment variable GYP_CHROMIUM_NO_ACTION=0.'
-    sys.exit(0)
-
   gyp_environment.set_environment()
 
   # This could give false positives since it doesn't actually do real option