Use chromium's gyp if third_party is not available.

platform_tools/android/bin/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/bin).
 SKIA_DIR = os.path.normpath(os.path.join(SCRIPT_DIR, os.pardir, os.pardir,
                                          os.pardir))
-dir_contents = os.listdir(SKIA_DIR)
-assert 'third_party' in dir_contents and 'gyp' in dir_contents
+DIR_CONTENTS = os.listdir(SKIA_DIR)
+assert 'gyp' in DIR_CONTENTS
 
 # Directory within which we can find the gyp source.
-GYP_SOURCE_DIR = os.path.join(SKIA_DIR, 'third_party', 'externals', 'gyp')
+if 'third_party' in DIR_CONTENTS:
+  GYP_SOURCE_DIR = os.path.join(SKIA_DIR, 'third_party', 'externals', 'gyp')
+else:
+  # 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')
+
+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'))
 
 import gyp
 
 def main(target_dir, target_file, skia_arch_type, have_neon):
   """
   Create gypd files based on target_file.
@@ skipping 33 matching lines @@
   if ret != 0:
     raise Exception("gyp failed!")
 
   # Running gyp should have created a gypd file, with the same name as
   # full_path but with a 'd' on the end.
   gypd_file = full_path + 'd'
   if not os.path.exists(gypd_file):
     raise Exception("gyp failed to produce gypd file!")
 
   return gypd_file