[DevTools] use debug_frontend flag in content_shell for tests

content/content_shell.gypi

 # 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': {
     'content_shell_product_name': 'Content Shell',
     'content_shell_version': '99.77.34.5',
     'conditions': [
       ['OS=="linux"', {
@@ skipping 263 matching lines @@
           'dependencies': [
             '../mojo/mojo_base.gyp:libmojo_system_java',
             'content_shell_jni_headers',
           ],
         }],  # OS=="android"
         ['os_posix == 1 and OS != "mac"', {
           'dependencies': [
             '../components/components.gyp:breakpad_host',
           ],
         }],
+        ['debug_devtools==1', {
+          'defines': [
+            'DEBUG_DEVTOOLS=1',
+          ],
+        }],
         ['(OS=="linux" or OS=="android") and use_allocator!="none"', {
           'dependencies': [
             # This is needed by content/app/content_main_runner.cc
             '../base/allocator/allocator.gyp:allocator',
           ],
         }],
         ['use_aura==1', {
           'dependencies': [
             '../ui/aura/aura.gyp:aura',
             '../ui/aura/aura.gyp:aura_test_support',
@@ skipping 694 matching lines @@
                 '--input_symbol', '<(PRODUCT_DIR)/content_shell.exe.pdb',
                 '--destination_dir', '<(dest_dir)',
               ],
             },
           ],
         },
       ],
     }],  # OS=="win" and fastbuild==0 and target_arch=="ia32"
   ]
 }