Make tools/run_hooks.py work when depot_tools is not in PATH

tools/run_hooks.py

Index: tools/run_hooks.py
diff --git a/tools/run_hooks.py b/tools/run_hooks.py
index 478391bbca482d5da9ea42424dff8001cfe40577..ed9671d32e884b35b0d78080221f4936108cd50f 100755
--- a/tools/run_hooks.py
+++ b/tools/run_hooks.py
@@ -23,11 +23,18 @@ def main(args):
   with open(deps_path) as deps_contents:
     d = deps_contents.read()
   exec(d, scope)
+  env = os.environ
+  # Some hooks expect depot_tools to be in the PATH already. If there is no
+  # depot_tools in the current environment's PATH add the default location of
+  # depot_tools in a standard checkout to the environment the hooks run in.
+  if env["PATH"].find("depot_tools") == -1:

[lanechr, 2016/03/04 17:35:41]

why not just add the default_depot_tools_path to the end of the PATH?  it would
better handle the case of the user having a depot_tools directory that doesn't
include the tool you want.  plus, this is kind of what PATH does.

+    default_depot_tools_path = os.path.join(gclient_path, "depot_tools")
+    env["PATH"] = env["PATH"] + ":" + default_depot_tools_path
   for hook in scope["hooks"]:
     name = hook["name"]
     print "________ running '%s' in '%s'" % (" ".join(hook["action"]),
         gclient_path)
-    subprocess.check_call(hook["action"], cwd=gclient_path)
+    subprocess.check_call(hook["action"], cwd=gclient_path, env=env)
     print
   return 0