Update from chromium https://crrev.com/302282

tools/vim/ninja-build.vim

 " 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.
 "
 " Adds a "Compile this file" function, using ninja. On Mac, binds Cmd-k to
 " this command. On Windows, Ctrl-F7 (which is the same as the VS default).
 " On Linux, <Leader>o, which is \o by default ("o"=creates .o files)
 "
 " Adds a "Build this target" function, using ninja. This is not bound
 " to any key by default, but can be used via the :CrBuild command.
@@ skipping 23 matching lines @@
   # would find "src/v8" for files below "src/v8", as "src/v8/build/common.gypi"
   # exists). The longer it is, the more likely it is to break when we rename
   # directories.
   fingerprints = ['chrome', 'net', 'v8', 'build', 'skia']
   while candidate and not all(
       [os.path.isdir(os.path.join(candidate, fp)) for fp in fingerprints]):
     candidate = os.path.dirname(candidate)
   return candidate
 
 
-def guess_configuration():
-  """Default to the configuration with either a newer build.ninja or a newer
-  protoc."""
-  root = os.path.join(path_to_source_root(), 'out')
-  def is_release_15s_newer(test_path):
-    try:
-      debug_mtime = os.path.getmtime(os.path.join(root, 'Debug', test_path))
-    except os.error:
-      debug_mtime = 0
-    try:
-      rel_mtime = os.path.getmtime(os.path.join(root, 'Release',  test_path))
-    except os.error:
-      rel_mtime = 0
-    return rel_mtime - debug_mtime >= 15
-  configuration = 'Debug'
-  if is_release_15s_newer('build.ninja') or is_release_15s_newer('protoc'):
-    configuration = 'Release'
-  return configuration
+def path_to_build_dir(configuration):
+  """Returns <chrome_root>/<output_dir>/(Release|Debug)."""
 
+  chrome_root = path_to_source_root()
+  sys.path.append(os.path.join(chrome_root, 'tools', 'vim'))
+  from ninja_output import GetNinjaOutputDirectory
+  return GetNinjaOutputDirectory(chrome_root, configuration)
 
 def compute_ninja_command_for_current_buffer(configuration=None):
   """Returns the shell command to compile the file in the current buffer."""
-  if not configuration: configuration = guess_configuration()
-  build_dir = os.path.join(path_to_source_root(), 'out', configuration)
+  build_dir = path_to_build_dir(configuration)
 
   # ninja needs filepaths for the ^ syntax to be relative to the
   # build directory.
   file_to_build = path_to_current_buffer()
   file_to_build = os.path.relpath(file_to_build, build_dir)
 
   build_cmd = ' '.join(['ninja', '-C', build_dir, file_to_build + '^'])
   if sys.platform == 'win32':
     # Escape \ for Vim, and ^ for both Vim and shell.
     build_cmd = build_cmd.replace('\\', '\\\\').replace('^', '^^^^')
   vim.command('return "%s"' % build_cmd)
 
 
 def compute_ninja_command_for_targets(targets='', configuration=None):
-  if not configuration: configuration = guess_configuration()
-  build_dir = os.path.join(path_to_source_root(), 'out', configuration)
-  build_cmd = ' '.join(['ninja', '-C', build_dir, targets])
+  build_cmd = ' '.join(['ninja', '-C', path_to_build_dir(configuration),
+                        targets])
   vim.command('return "%s"' % build_cmd)
 endpython
 
 fun! s:MakeWithCustomCommand(build_cmd)
   let l:oldmakepgr = &makeprg
   let &makeprg=a:build_cmd
   silent make | cwindow
   if !has('gui_running')
     redraw!
   endif
@@ skipping 25 matching lines @@
 
 if has('mac')
   map <D-k> :CrCompileFile<cr>
   imap <D-k> <esc>:CrCompileFile<cr>
 elseif has('win32')
   map <C-F7> :CrCompileFile<cr>
   imap <C-F7> <esc>:CrCompileFile<cr>
 elseif has('unix')
   map <Leader>o :CrCompileFile<cr>
 endif