Wrap ninja invocation to include python in path, and set up compiler...

Wrap ninja invocation to include python in path, and set up compiler environment before invoking the ninja binary itself (which is moved to a subdirectory).
Review URL: https://chromiumcodereview.appspot.com/9967020

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@132239 0039d316-1c4b-4281-b951-d872f2087c98

ninja.bat

+@echo off
+
+:: Copyright (c) 2012 Google Inc. All rights reserved.
+:: Use of this source code is governed by a BSD-style license that can be
+:: found in the LICENSE file.
+
+setlocal enabledelayedexpansion
+
+:: Parse args to see if a -C argument (to change working directory) is being
+:: supplied. We expect project generation to output a set_environment.bat that
+:: will set up the environment (variables and path). This script generally
+:: just calls the correct VS vars batch file, but only gyp has the knowledge
+:: to determine which version of the IDE/toolchain it wants to use, so we have
+:: to defer to it to make that decision.
+set found_dash_c=0
+set cd_path=.
+for %%A in (%*) do (
+  if "!found_dash_c!"=="1" (
+    set cd_path=%%A
+    goto done_dash_c
+  )
+  if "%%A"=="-C" (
+    set found_dash_c=1
+  )
+)
+:done_dash_c
+
+if not exist "%cd_path%\set_environment.bat" (
+  echo ninja.bat: set_environment.bat not found in '%cd_path%'. Is -C arg correct?
+  goto :EOF
+)
+call "%cd_path%\set_environment.bat"
+
+:: Add python to the path, many gyp rules assume it's there.
+:: Add ninja directory to the path (to find ninja and ninja-deplist-helper).
+:: Then, export only the path changes out of the script so that next time we
+:: just run ninja directly (otherwise, this script adds about 500-800ms to
+:: ninja invocations).
+endlocal & set PATH=%~dp0python_bin;%~dp0ninja-win;%PATH% & set INCLUDE=%INCLUDE% & set LIBPATH=%LIBPATH% & set LIB=%LIB%
+
+:: Now run the actual build.
+ninja.exe %*