Remove the chrome include in extensions\DEPS by creating a test data directory for extensions.

chrome/unit_tests.isolate

 # 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.
 {
   'variables': {
     'isolate_dependency_tracked': [
       '<(PRODUCT_DIR)/resources.pak',
       '<(PRODUCT_DIR)/unit_tests<(EXECUTABLE_SUFFIX)',
       'browser/safe_browsing/two_phase_testserver.py',
     ],
     'isolate_dependency_untracked': [
       '../base/prefs/test/data/',
+      '../extensions/test/data/',
       '../net/data/',
       '../net/tools/testserver/',
       '../testing/test_env.py',
       '../third_party/hunspell_dictionaries/',
       '../third_party/pyftpdlib/',
       '../third_party/pywebsocket/',
       '../third_party/tlslite/',
       '../tools/swarm_client/',
       'third_party/mock4js/',
       'test/data/',
@@ skipping 67 matching lines @@
           '../ppapi/lib/gl/include/KHR/',
           '../skia/ext/data/',
           '../third_party/python_26/',
           '../ui/base/glib/',
           '<(PRODUCT_DIR)/test_data/ui/',
         ],
       },
     }],
   ],
 }