Move extensions-related files to using //components/keyed_service.

extensions/browser/extension_system.h

Index: extensions/browser/extension_system.h
diff --git a/extensions/browser/extension_system.h b/extensions/browser/extension_system.h
index b1e724c2bba7945ac19cf0e38099d534a149e4bd..91acb749e430953002ce1dbd3b89731770380ab4 100644
--- a/extensions/browser/extension_system.h
+++ b/extensions/browser/extension_system.h
@@ -8,7 +8,7 @@
 #include <string>
 
 #include "base/memory/ref_counted.h"
-#include "components/browser_context_keyed_service/browser_context_keyed_service.h"
+#include "components/keyed_service/core/keyed_service.h"
 #include "extensions/common/extension.h"
 
 class ExtensionService;
@@ -45,7 +45,7 @@ class UserScriptMaster;
 // extensions and apps system, and it handles startup and shutdown as needed.
 // Eventually, we'd like to make more of these services into
 // BrowserContextKeyedServices in their own right.
-class ExtensionSystem : public BrowserContextKeyedService {
+class ExtensionSystem : public KeyedService {
  public:
   ExtensionSystem();
   virtual ~ExtensionSystem();