Allow chrome.debugger API to attach to extension background pages.

chrome/browser/about_flags.cc

 // 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.
 
 #include "chrome/browser/about_flags.h"
 
 #include <algorithm>
 #include <iterator>
 #include <map>
 #include <set>
@@ skipping 771 matching lines @@
   },
 #endif
   {
     "enable-devtools-experiments",
     IDS_FLAGS_ENABLE_DEVTOOLS_EXPERIMENTS_NAME,
     IDS_FLAGS_ENABLE_DEVTOOLS_EXPERIMENTS_DESCRIPTION,
     kOsDesktop,
     SINGLE_VALUE_TYPE(switches::kEnableDevToolsExperiments)
   },
   {
+    "silent-debugger-extension-api",
+    IDS_FLAGS_SILENT_DEBUGGER_EXTENSION_API_NAME,
+    IDS_FLAGS_SILENT_DEBUGGER_EXTENSION_API_DESCRIPTION,
+    kOsDesktop,
+    SINGLE_VALUE_TYPE(switches::kSilentDebuggerExtensionAPI)
+  },
+  {
     "enable-suggestions-ntp",
     IDS_FLAGS_NTP_SUGGESTIONS_PAGE_NAME,
     IDS_FLAGS_NTP_SUGGESTIONS_PAGE_DESCRIPTION,
     kOsDesktop,
     SINGLE_VALUE_TYPE(switches::kEnableSuggestionsTabPage)
   },
   {
     "spellcheck-autocorrect",
     IDS_FLAGS_SPELLCHECK_AUTOCORRECT,
     IDS_FLAGS_SPELLCHECK_AUTOCORRECT_DESCRIPTION,
@@ skipping 930 matching lines @@
 }
 
 const Experiment* GetExperiments(size_t* count) {
   *count = num_experiments;
   return experiments;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags