Add presubmit check to prevent package boundary violations.

PRESUBMIT.py

 # Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import json
 import os
 import re
+import subprocess
 import sys
 
 
 # Directories that will be scanned by cpplint by the presubmit script.
 CPPLINT_DIRS = [
   'webrtc/audio',
   'webrtc/call',
   'webrtc/common_video',
   'webrtc/examples',
   'webrtc/modules/audio_mixer',
@@ skipping 55 matching lines @@
   'webrtc/modules/video_coding/codecs/i420/include',
   'webrtc/modules/video_coding/codecs/vp8/include',
   'webrtc/modules/video_coding/codecs/vp9/include',
   'webrtc/modules/video_coding/include',
   'webrtc/system_wrappers/include',
   'webrtc/voice_engine/include',
 )
 API_DIRS = NATIVE_API_DIRS[:] + LEGACY_API_DIRS[:]
 
 
+def _RunCommand(command, cwd):
+  """Runs a command and returns the output from that command."""
+  p = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+                       cwd=cwd)
+  stdout = p.stdout.read()
+  stderr = p.stderr.read()
+  p.wait()
+  p.stdout.close()
+  p.stderr.close()
+  return p.returncode, stdout, stderr
+
+
 def _VerifyNativeApiHeadersListIsValid(input_api, output_api):
   """Ensures the list of native API header directories is up to date."""
   non_existing_paths = []
   native_api_full_paths = [
       input_api.os_path.join(input_api.PresubmitLocalPath(),
                              *path.split('/')) for path in API_DIRS]
   for path in native_api_full_paths:
     if not os.path.isdir(path):
       non_existing_paths.append(path)
   if non_existing_paths:
@@ skipping 181 matching lines @@
   if violating_gn_files:
     return [output_api.PresubmitError(
         'GN targets cannot mix .cc and .c source files. Please create a '
         'separate target for each collection of sources.\n'
         'Mixed sources: \n'
         '%s\n'
         'Violating GN files:' % json.dumps(violating_gn_files, indent=2),
         items=violating_gn_files.keys())]
   return []
 
+def _CheckNoPackageBoundaryViolations(input_api, gn_files, output_api):
+  cwd = input_api.PresubmitLocalPath()
+  script_path = os.path.join('tools-webrtc', 'check_package_boundaries.py')
+  webrtc_path = os.path.join('webrtc')
+  command = ['python', script_path, '--max_messages=1', webrtc_path]
+  command += [gn_file.LocalPath() for gn_file in gn_files]
+  returncode, _, stderr = _RunCommand(command, cwd)
+  if returncode:
+    return [output_api.PresubmitError(
+        'There are package boundary violations in the following GN files:\n\n'

[kjellander_webrtc, 2017/01/16 07:26:10]

I think since most people are not familiar with what package boundary violations
are you need to either explain in detail or link to Bazel docs about it

[ehmaldonado_webrtc, 2017/01/16 08:52:50]

Acknowledged.

+        '%s' % stderr)]
+  return []
+
 def _CheckGnChanges(input_api, output_api):
   source_file_filter = lambda x: input_api.FilterSourceFile(
       x, white_list=(r'.+\.(gn|gni)$',))
 
   gn_files = []
   for f in input_api.AffectedSourceFiles(source_file_filter):
     if f.LocalPath().startswith('webrtc'):
       gn_files.append(f)
 
   result = []
   if gn_files:
     result.extend(_CheckNoSourcesAbove(input_api, gn_files, output_api))
     result.extend(_CheckNoMixingCAndCCSources(input_api, gn_files, output_api))
+    result.extend(_CheckNoPackageBoundaryViolations(
+        input_api, gn_files, output_api))
   return result
 
 def _CheckUnwantedDependencies(input_api, output_api):
   """Runs checkdeps on #include statements added in this
   change. Breaking - rules is an error, breaking ! rules is a
   warning.
   """
   # Copied from Chromium's src/PRESUBMIT.py.
 
   # We need to wait until we have an input_api object and use this
@@ skipping 196 matching lines @@
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasDescription(
       input_api, output_api))
   results.extend(_CheckChangeHasBugField(input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasTestField(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckTreeIsOpen(
       input_api, output_api,
       json_url='http://webrtc-status.appspot.com/current?format=json'))
   return results