Change clang_format.py to search for clang-format in buildtools

gclient_utils.py

Index: gclient_utils.py
diff --git a/gclient_utils.py b/gclient_utils.py
index 655e5aa1b704e9c49dd0d626fe72c191201aa80f..9837cbb36c777dfdac67e4a7148dd5c48e1441b9 100644
--- a/gclient_utils.py
+++ b/gclient_utils.py
@@ -655,6 +655,19 @@ def GetBuildtoolsPath():
   This is based on the root of the checkout containing the current directory."""
   gclient_root = FindGclientRoot(os.getcwd())
   if not gclient_root:
+    # Some projects might not use .gclient. Try to see whether we're in a git
+    # checkout.
+    top_dir = [os.getcwd()]
+    def filter_fn(line):
+      top_dir[0] = os.path.normpath(line.rstrip('\n'))
+    try:
+      CheckCallAndFilter(["git", "rev-parse", "--show-toplevel"],
+                         print_stdout=False, filter_fn=filter_fn)
+    except Exception:
+      pass
+    top_dir = top_dir[0]
+    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')