Remove //chrome dependency from ExtensionPrefs

extensions/browser/extension_prefs_observer.h

+// 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.
+
+#ifndef EXTENSIONS_BROWSER_EXTENSION_PREFS_OBSERVER_H_
+#define EXTENSIONS_BROWSER_EXTENSION_PREFS_OBSERVER_H_
+
+#include <string>
+
+#include "base/time/time.h"
+
+namespace extensions {
+
+class ExtensionPrefsObserver {
+ public:
+  // Called when the reasons for an extension being disabled have changed.
+  virtual void OnExtensionDisableReasonsChanged(const std::string& extension_id,
+                                                int disabled_reasons) {}
+
+  // Called when an extension is registered with ExtensionPrefs.
+  virtual void OnExtensionRegistered(const std::string& extension_id,
+                                     const base::Time& install_time,
+                                     bool is_enabled) {}
+
+  // Called when an extension's prefs have been loaded.
+  virtual void OnExtensionPrefsLoaded(const std::string& extension_id) {}
+
+  // Called when an extension's prefs are deleted.
+  virtual void OnExtensionPrefsDeleted(const std::string& extension_id) {}
+
+  // Called when an extension's enabled state pref is changed.
+  virtual void OnExtensionStateChanged(const std::string& extension_id,
+                                       bool state) {}
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_EXTENSION_PREFS_OBSERVER_H_