Implement <appview>

chrome/browser/guest_view/app_view/app_view_constants.h

Index: chrome/browser/guest_view/app_view/app_view_constants.h
diff --git a/chrome/browser/guest_view/app_view/app_view_constants.h b/chrome/browser/guest_view/app_view/app_view_constants.h
new file mode 100644
index 0000000000000000000000000000000000000000..734dbd5b808c2aa7727d28ed258ddf5698134d69
--- /dev/null
+++ b/chrome/browser/guest_view/app_view/app_view_constants.h
@@ -0,0 +1,19 @@
+// 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.
+
+// Constants used for the AppView API.
+
+#ifndef CHROME_BROWSER_GUEST_VIEW_APP_VIEW_APP_VIEW_CONSTANTS_H_
+#define CHROME_BROWSER_GUEST_VIEW_APP_VIEW_APP_VIEW_CONSTANTS_H_
+
+namespace appview {
+
+// Parameters/properties on events.
+extern const char kAppID[];
+extern const char kEmbedderExtensionID[];
+extern const char kGuestInstanceID[];
+
+}  // namespace appview
+
+#endif  // CHROME_BROWSER_GUEST_VIEW_APP_VIEW_APP_VIEW_CONSTANTS_H_