Remove //chrome dependency from ExtensionPrefs

chrome/browser/extensions/chrome_extensions_browser_client.cc

Index: chrome/browser/extensions/chrome_extensions_browser_client.cc
diff --git a/chrome/browser/extensions/chrome_extensions_browser_client.cc b/chrome/browser/extensions/chrome_extensions_browser_client.cc
index 67d76bd16bed8a6df3f8b6e7de7bab9062f58ccc..ffa47b0f1c8fbecb3c98130feb1e8eed4c5b1dd0 100644
--- a/chrome/browser/extensions/chrome_extensions_browser_client.cc
+++ b/chrome/browser/extensions/chrome_extensions_browser_client.cc
@@ -37,6 +37,7 @@
 
 #if defined(ENABLE_EXTENSIONS)
 #include "chrome/browser/extensions/api/chrome_extensions_api_client.h"
+#include "chrome/browser/extensions/api/content_settings/content_settings_service.h"
 #endif
 
 namespace extensions {
@@ -116,6 +117,14 @@ PrefService* ChromeExtensionsBrowserClient::GetPrefServiceForContext(
   return static_cast<Profile*>(context)->GetPrefs();
 }
 
+void ChromeExtensionsBrowserClient::GetEarlyExtensionPrefsObservers(
+    content::BrowserContext* context,
+    std::vector<ExtensionPrefsObserver*>* observers) const {
+#if defined(ENABLE_EXTENSIONS)
+  observers->push_back(ContentSettingsService::Get(context));
+#endif
+}
+
 bool ChromeExtensionsBrowserClient::DeferLoadingBackgroundHosts(
     content::BrowserContext* context) const {
   Profile* profile = static_cast<Profile*>(context);