[remoting android] Generate trimmed-down credits.html.

tools/licenses.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Utility for checking and processing licensing information in third_party
 directories.
 
 Usage: licenses.py <command>
 
@@ skipping 444 matching lines @@
             third_party_dirs.add(dir)
 
     return third_party_dirs
 
 
 def FindThirdPartyDirsWithFiles(root):
     third_party_dirs = FindThirdPartyDirs(PRUNE_PATHS, root)
     return FilterDirsWithFiles(third_party_dirs, root)
 
 
+# Many builders do not contain 'gn' in their PATH, so use the GN binary from
+# //buildtools.
+def _GnBinary():
+    exe = 'gn'
+    if sys.platform == 'linux2':
+        subdir = 'linux64'
+    elif sys.platform == 'darwin':
+        subdir = 'mac'
+    elif sys.platform == 'win32':
+        subdir, exe = 'win', 'gn.exe'
+    else:
+        raise RuntimeError("Unsupported platform '%s'." % sys.platform)
+
+    return os.path.join(_REPOSITORY_ROOT, 'buildtools', subdir, exe)
+
+
 def FindThirdPartyDeps(gn_out_dir, gn_target):
     if not gn_out_dir:
         raise RuntimeError("--gn-out-dir is required if --gn-target is used.")
 
-    gn_deps = subprocess.check_output(["gn", "desc", gn_out_dir, gn_target,
+    gn_deps = subprocess.check_output([_GnBinary(), "desc", gn_out_dir,
+                                       gn_target,
                                        "deps", "--as=buildfile", "--all"])
     third_party_deps = set()
     for build_dep in gn_deps.split():
         if ("third_party" in build_dep and
                 os.path.basename(build_dep) == "BUILD.gn"):
             third_party_deps.add(os.path.dirname(build_dep))
     return third_party_deps
 
 
 def ScanThirdPartyDirs(root=None):
@@ skipping 134 matching lines @@
                                args.output_file, args.target_os,
                                args.gn_out_dir, args.gn_target, args.depfile):
             return 1
     else:
         print __doc__
         return 1
 
 
 if __name__ == '__main__':
   sys.exit(main())