Remove //chrome dependency from ExtensionPrefs

extensions/browser/extension_prefs_factory.cc

 // 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.
 
 #include "base/command_line.h"
 #include "base/prefs/pref_service.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "content/public/browser/browser_context.h"
 #include "extensions/browser/extension_pref_value_map.h"
 #include "extensions/browser/extension_pref_value_map_factory.h"
@@ skipping 26 matching lines @@
           "ExtensionPrefs",
           BrowserContextDependencyManager::GetInstance()) {
 }
 
 ExtensionPrefsFactory::~ExtensionPrefsFactory() {
 }
 
 KeyedService* ExtensionPrefsFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   ExtensionsBrowserClient* client = ExtensionsBrowserClient::Get();
-  return ExtensionPrefs::Create(
+  ExtensionPrefs* prefs = ExtensionPrefs::Create(
       client->GetPrefServiceForContext(context),
       context->GetPath().AppendASCII(extensions::kInstallDirectoryName),
       ExtensionPrefValueMapFactory::GetForBrowserContext(context),
       client->CreateAppSorting().Pass(),
-      client->AreExtensionsDisabled(
-          *CommandLine::ForCurrentProcess(), context));
+      client->AreExtensionsDisabled(*CommandLine::ForCurrentProcess(),

[James Cook, 2014/04/01 18:45:03]

Another way to do this might be to pass an optional observer into the Create()
method.

[Ken Rockot(use gerrit already), 2014/04/01 21:34:59]

True. I like this. Actually I'm going to have it take a vector of early
observers (I can't stomach adding a single special observer argument!) The EBC
method will populate a vector of observers.

ExtensionPrefsFactory will use this to populate its argument to Create.

+                                    context));
+  client->AddExtensionPrefsObservers(context, prefs);
+  prefs->Initialize();
+  return prefs;
 }
 
 content::BrowserContext* ExtensionPrefsFactory::GetBrowserContextToUse(
     content::BrowserContext* context) const {
   return ExtensionsBrowserClient::Get()->GetOriginalContext(context);
 }
 
 }  // namespace extensions