new_contents: # Copyright 2012 the V8 project authors. All rights reserved.
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are
  # met:
  #
  #     * Redistributions of source code must retain the above copyright
  #       notice, this list of conditions and the following disclaimer.
  #     * Redistributions in binary form must reproduce the above
  #       copyright notice, this list of conditions and the following
  #       disclaimer in the documentation and/or other materials provided
  #       with the distribution.
  #     * Neither the name of Google Inc. nor the names of its
  #       contributors may be used to endorse or promote products derived
  #       from this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  """Top-level presubmit script for V8.
  
  See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
  for more details about the presubmit API built into gcl.
  """
  
  def _V8PresubmitChecks(input_api, output_api):
    """Runs the V8 presubmit checks."""
    import sys
    sys.path.append(input_api.os_path.join(
          input_api.PresubmitLocalPath(), 'tools'))
    from presubmit import CppLintProcessor
    from presubmit import SourceProcessor
  
    results = []
    if not CppLintProcessor().Run(input_api.PresubmitLocalPath()):
      results.append(output_api.PresubmitError("C++ lint check failed"))
    if not SourceProcessor().Run(input_api.PresubmitLocalPath()):
      results.append(output_api.PresubmitError(
          "Copyright header and trailing whitespaces check failed"))
    return results
  
  
  def _CommonChecks(input_api, output_api):
    """Checks common to both upload and commit."""
    results = []
    results.extend(input_api.canned_checks.CheckOwners(
        input_api, output_api, source_file_filter=None))
    return results
  
  
  def CheckChangeOnUpload(input_api, output_api):
    results = []
    results.extend(_CommonChecks(input_api, output_api))
    return results
  
  
  def CheckChangeOnCommit(input_api, output_api):
    results = []
    results.extend(_CommonChecks(input_api, output_api))
    results.extend(input_api.canned_checks.CheckChangeHasDescription(
        input_api, output_api))
    results.extend(_V8PresubmitChecks(input_api, output_api))
    return results
  
subject: Add PRESUBMIT script to V8