If our gyp does not exist, use chromium's.

platform_tools/android/gyp_gen/android_framework_gyp.py

 #!/usr/bin/python
 
 # Copyright 2014 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Modified version of gyp_skia, used by gyp_to_android.py to generate Android.mk
 """
 
 import os
 import sys
 
 SCRIPT_DIR = os.path.abspath(os.path.dirname(__file__))
 
 # Unlike gyp_skia, this file is nested deep inside Skia. Find Skia's trunk dir.
 # This line depends on the fact that the script is three levels deep
 # (specifically, it is in platform_tools/android/gyp_gen).
 SKIA_DIR = os.path.normpath(os.path.join(SCRIPT_DIR, os.pardir, os.pardir,
                                          os.pardir))
 DIR_CONTENTS = os.listdir(SKIA_DIR)
 assert 'gyp' in DIR_CONTENTS
 
 # Directory within which we can find the gyp source.
-if 'third_party' in DIR_CONTENTS:
-  GYP_SOURCE_DIR = os.path.join(SKIA_DIR, 'third_party', 'externals', 'gyp')
-else:
+gyp_source_dir = os.path.join(SKIA_DIR, 'third_party', 'externals', 'gyp')
+if not os.path.exists(gyp_source_dir):
   # In an Android tree, there is no third_party/externals/gyp, which would
   # require running gclient sync. Use chromium's instead.
-  GYP_SOURCE_DIR = os.path.join(SKIA_DIR, os.pardir, 'chromium_org', 'tools',
+  gyp_source_dir = os.path.join(SKIA_DIR, os.pardir, 'chromium_org', 'tools',
                                 'gyp')
 
-assert os.path.exists(GYP_SOURCE_DIR)
+assert os.path.exists(gyp_source_dir)
 
 # Ensure we import our current gyp source's module, not any version
 # pre-installed in your PYTHONPATH.
-sys.path.insert(0, os.path.join(GYP_SOURCE_DIR, 'pylib'))
+sys.path.insert(0, os.path.join(gyp_source_dir, 'pylib'))
 
 import gyp
 
 def main(target_dir, target_file, skia_arch_type, have_neon):
   """Create gypd files based on target_file.
 
   Args:
     target_dir: Directory containing all gyp files, including common.gypi
     target_file: Gyp file to start on. Other files within target_dir will
       be read if target_file depends on them.
@@ skipping 45 matching lines @@
   """Remove the gypd files generated by main().
 
   Args:
     folder: Folder in which to delete all files ending with 'gypd'.
   """
   assert os.path.isdir(folder)
   files = os.listdir(folder)
   for f in files:
     if f.endswith('gypd'):
       os.remove(os.path.join(folder, f))