Add IGNORE_DEPS_CHANGES flag and coverage builder.

scripts/slave/recipe_modules/chromium_tests/chromium_chromiumos.py

 # Copyright 2014 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.
 
 from . import steps
 
 SPEC = {
   'settings': {
     'build_gs_bucket': 'chromium-chromiumos-archive',
     # WARNING: src-side runtest.py is only tested with chromium CQ builders.
@@ skipping 152 matching lines @@
         'BUILD_CONFIG': 'Debug',
         'TARGET_BITS': 64,
       },
       'bot_type': 'tester',
       'parent_buildername': 'Linux ChromiumOS Builder (dbg)',
       'testing': {
         'platform': 'linux',
       },
       'enable_swarming': True,
     },
+
+    # Add a coverage builder to exercise configs that are leveraged in other
+    # recipe collections to build chrome packages:
+    # - "ignore_deps_changes"
+    'Package Builder (Coverage)': {
+      'chromium_config': 'chromium',
+      'chromium_apply_config': ['chromeos', 'ninja_confirm_noop',
+                                'ignore_deps_changes', 'mb'],
+      'gclient_config': 'chromium',
+      'chromium_config_kwargs': {
+        'BUILD_CONFIG': 'Debug',
+        'TARGET_BITS': 64,
+      },
+      'bot_type': 'builder',
+      'testing': {
+        'platform': 'linux',
+      },
+    },
   },
 }
 
 # Simple Chrome compile-only builders.
 for board in ('x86-generic', 'amd64-generic', 'daisy'):
   SPEC['builders']['ChromiumOS %s Compile' % (board,)] = {
     'chromium_config': 'chromium',
     'chromium_apply_config': ['chromeos', 'mb', 'ninja_confirm_noop'],
     'gclient_config': 'chromium',
     'chromium_config_kwargs': {
       'BUILD_CONFIG': 'Release',
       'TARGET_PLATFORM': 'chromeos',
       'TARGET_CROS_BOARD': board,
     },
     'bot_type': 'builder',
     'compile_targets': [
       'chromiumos_preflight',
     ],
     'testing': {
       'platform': 'linux',
     },
   }