Skip GYP if GYP_PDFIUM_NO_ACTION set.

build_gyp/gyp_pdfium

Index: build_gyp/gyp_pdfium
diff --git a/build_gyp/gyp_pdfium b/build_gyp/gyp_pdfium
index c65337861ee1cdab73ada6b5f7ff19cfca13e09a..c79593b9907629cb15d698db916afcbb4e31552e 100755
--- a/build_gyp/gyp_pdfium
+++ b/build_gyp/gyp_pdfium
@@ -26,6 +26,10 @@ def run_gyp(args):
 
 
 def main():
+  if int(os.environ.get('GYP_PDFIUM_NO_ACTION', 0)):
+    print 'Skipping gyp_pdfium due to GYP_PDFIUM_NO_ACTION env var.'
+    sys.exit(0)
+
   args = sys.argv[1:]
   args.append(os.path.join(pdfium_root, 'build_gyp', 'all.gyp'))