Make gn.py support root directories other than 'src'.

gclient_utils.py

Index: gclient_utils.py
diff --git a/gclient_utils.py b/gclient_utils.py
index e8d916e78d5d2a8aeba4cbf61bebf7b64ad79084..7cc42a6a3ebcfd19ca16e57bb0cabe5afa27cd52 100644
--- a/gclient_utils.py
+++ b/gclient_utils.py
@@ -681,7 +681,10 @@ def GetBuildtoolsPath():
     if os.path.exists(os.path.join(top_dir, 'buildtools')):
       return os.path.join(top_dir, 'buildtools')
     return None
-  return os.path.join(gclient_root, 'src', 'buildtools')
+
+  # Some projects' top directory is not named 'src'.
+  source_dir_name = GetGClientPrimarySolutionName(gclient_root) or 'src'
+  return os.path.join(gclient_root, source_dir_name, 'buildtools')
 
 
 def GetBuildtoolsPlatformBinaryPath():
@@ -713,6 +716,18 @@ def GetExeSuffix():
   return ''
 
 
+def GetGClientPrimarySolutionName(gclient_root_dir_path):
+  """Returns the name of the primary solution in the .gclient file specified."""
+  gclient_config_file = os.path.join(gclient_root_dir_path, '.gclient')
+  env = {}
+  execfile(gclient_config_file, env)
+  if (env.has_key('solutions') and

[agable, 2014/09/05 11:31:53]

I would rewrite this clause as:
solutions = env.get('solutions', [])
if solutions:
  return solutions[0].get('name')

I think this is easier to read than a triple conjunction, and it will default to
returning None if 'solutions' or 'name' don't exist.

[kjellander_chromium, 2014/09/05 12:24:31]

You're right. Covering the case with zero solutions in the list is highly
unlikely to happen.

+      len(env['solutions']) > 0 and
+      env['solutions'][0].has_key('name')):
+    return env['solutions'][0]['name']
+  return None
+
+
 def GetGClientRootAndEntries(path=None):
   """Returns the gclient root and the dict of entries."""
   config_file = '.gclient_entries'