Add depfile support to android build scripts

build/android/gyp/util/build_utils.py

Index: build/android/gyp/util/build_utils.py
diff --git a/build/android/gyp/util/build_utils.py b/build/android/gyp/util/build_utils.py
index 0b4466d440ea2283340fdeec9d63aa973e801c14..1ab76b30c938f68a96a5aaa11445138ce5fd9a57 100644
--- a/build/android/gyp/util/build_utils.py
+++ b/build/android/gyp/util/build_utils.py
@@ -82,6 +82,7 @@ def CheckOptions(options, parser, required=None):
     if getattr(options, option_name) is None:
       parser.error('--%s is required' % option_name.replace('_', '-'))
 
+
 def WriteJson(obj, path, only_if_changed=False):
   old_dump = None
   if os.path.exists(path):
@@ -94,6 +95,7 @@ def WriteJson(obj, path, only_if_changed=False):
     with open(path, 'w') as outfile:
       outfile.write(new_dump)
 
+
 def ReadJson(path):
   with open(path, 'r') as jsonfile:
     return json.load(jsonfile)
@@ -212,3 +214,38 @@ def PrintBigWarning(message):
   print '*****     ' * 8
   PrintWarning(message)
   print '*****     ' * 8
+
+
+def GetPythonDependencies():
+  """Gets the paths of imported non-system python modules."""
+  module_paths = (m.__file__ for m in sys.modules.itervalues()
+                  if m is not None and hasattr(m, '__file__'))
+
+  abs_module_paths = map(os.path.abspath, module_paths)
+
+  chromium_src = os.path.abspath(
+      os.path.join(__file__, '..', '..', '..', '..'))
+
+  non_system_module_paths = [
+      p for p in abs_module_paths if p.startswith(chromium_src)]

[Nico, 2014/06/23 15:32:00]

See thread ".d files and absolute paths" on gn-dev where the conclusion was """
I would expect .d files to allow me to follow the same rules I do for
writing .ninja files. GN's current rules are to write relative paths
for anything inside the source root ("src/") (probably excepting the
case where the build directory is not inside the source root), and
absolute paths other times.
"""

[cjhopman, 2014/06/23 17:26:56]

Done.

+  def ConvertPycToPy(s):
+    if s.endswith('.pyc'):
+      return s[:-1]
+    return s
+
+  non_system_module_paths = map(ConvertPycToPy, non_system_module_paths)
+  return list(set(non_system_module_paths))

[Nico, 2014/06/23 15:32:00]

set() means this won't have a deterministic order

[cjhopman, 2014/06/23 17:26:56]

Done.

+
+
+def AddDepfileOption(parser):
+  parser.add_option('--depfile',
+                    help='Path to depfile. This should be specified as the '
+                    'action\'s first output.')
+
+
+def WriteDepfile(path, dependencies):
+  with open(path, 'w') as depfile:
+    depfile.write(path)
+    depfile.write(': ')
+    depfile.write(' '.join(dependencies))
+    depfile.write('\n')