Implement declarativeContent API.

chrome/browser/extensions/api/declarative_content/content_constants.h

Index: chrome/browser/extensions/api/declarative_content/content_constants.h
diff --git a/chrome/browser/extensions/api/declarative_content/content_constants.h b/chrome/browser/extensions/api/declarative_content/content_constants.h
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+// Copyright (c) 2012 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.
+
+// Constants used for the declarativeContent API.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_CONTENT_CONTENT_CONSTANTS_H_
+#define CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_CONTENT_CONTENT_CONSTANTS_H_
+
+namespace extensions {
+namespace declarative_content_constants {
+
+// Signals to which ContentRulesRegistries are registered.
+extern const char kOnPageChanged[];
+
+// Keys of dictionaries.
+extern const char kCss[];
+extern const char kInstanceType[];
+extern const char kTopUrl[];
+
+// Values of dictionaries, in particular instance types
+extern const char kPageStateMatcherType[];
+extern const char kShowPageAction[];
+
+}  // namespace declarative_content_constants
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_CONTENT_CONTENT_CONSTANTS_H_