Make the hcsm and its providers communicate via an observer interface.

chrome/browser/content_settings/content_settings_mock_observer.h

Index: chrome/browser/content_settings/content_settings_mock_observer.h
diff --git a/chrome/browser/content_settings/content_settings_mock_observer.h b/chrome/browser/content_settings/content_settings_mock_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..06e2c7a3065fae1bc1d26e66ea9ad7decb9f5e82
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+++ b/chrome/browser/content_settings/content_settings_mock_observer.h
@@ -0,0 +1,28 @@
+// Copyright (c) 2011 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 CHROME_BROWSER_CONTENT_SETTINGS_CONTENT_SETTINGS_MOCK_OBSERVER_H_
+#define CHROME_BROWSER_CONTENT_SETTINGS_CONTENT_SETTINGS_MOCK_OBSERVER_H_
+
+#include <string>
+
+#include "chrome/browser/content_settings/content_settings_observer.h"
+#include "testing/gmock/include/gmock/gmock.h"
+
+namespace content_settings {
+
+class MockObserver : public Observer {
+ public:
+  MockObserver() { }
+  virtual ~MockObserver()  {}
+
+  MOCK_METHOD4(OnContentSettingChanged,
+               void(ContentSettingsPattern primary_pattern,
+                    ContentSettingsPattern secondary_pattern,
+                    ContentSettingsType content_type,
+                    std::string resource_identifier));
+};
+}  // content_settings
+
+#endif  // CHROME_BROWSER_CONTENT_SETTINGS_CONTENT_SETTINGS_MOCK_OBSERVER_H_