[Cronet] Add presubmit check to verify Cronet package division.

components/cronet/PRESUBMIT.py

 # Copyright 2015 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.
 
 """Top-level presubmit script for src/components/cronet.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into depot_tools.
 """
 
@@ skipping 13 matching lines @@
     input_api.os_path.join(chromium_src_dir, 'build', 'android', 'gyp', 'util'),
     input_api.os_path.join(chromium_src_dir, 'net', 'tools', 'net_docs'),
     input_api.os_path.join(chromium_src_dir, 'tools'),
     input_api.os_path.join(chromium_src_dir, 'third_party'),
     input_api.os_path.join(chromium_src_dir,
         'third_party', 'catapult', 'telemetry'),
     input_api.os_path.join(chromium_src_dir,
         'third_party', 'catapult', 'devil'),
   ]
 
+def _PackageChecks(input_api, output_api):
+  """Verify API classes are in org.chromium.net package, and implementation
+  classes are not in org.chromium.net package."""
+  api_file_pattern = input_api.re.compile(
+      r'^components/cronet/android/api/.*\.(java|template)$')
+  impl_file_pattern = input_api.re.compile(
+      r'^components/cronet/android/java/.*\.(java|template)$')
+  api_package_pattern = input_api.re.compile(r'^package (?!org.chromium.net;)')
+  impl_package_pattern = input_api.re.compile(r'^package org.chromium.net;')
+
+  source_filter = lambda path: input_api.FilterSourceFile(path,
+      white_list=[r'^components/cronet/android/.*\.(java|template)$'])
+
+  problems = []
+  for f in input_api.AffectedSourceFiles(source_filter):
+    local_path = f.LocalPath()
+    for line_number, line in f.ChangedContents():
+      if (api_file_pattern.search(local_path)):
+        if (api_package_pattern.search(line)):
+          problems.append(
+            '%s:%d\n    %s' % (local_path, line_number, line.strip()))
+      elif (impl_file_pattern.search(local_path)):
+        if (impl_package_pattern.search(line)):
+          problems.append(
+            '%s:%d\n    %s' % (local_path, line_number, line.strip()))
+
+  if problems:
+    return [output_api.PresubmitError(
+        'API classes must be in org.chromium.net package, and implementation\n'
+        'classes must not be in org.chromium.net package.',
+        problems)]
+  else:
+    return []
+
 def CheckChangeOnUpload(input_api, output_api):
   results = []
   results.extend(_PyLintChecks(input_api, output_api))
   results.extend(
       input_api.canned_checks.CheckPatchFormatted(input_api, output_api))
+  results.extend(_PackageChecks(input_api, output_api))
   return results