Implement declarativeContent API.

chrome/common/extensions/extension_messages.h

 // 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.
 
 // IPC messages for extensions.
 // Multiply-included message file, hence no include guard.
 
 #include "base/shared_memory.h"
 #include "base/values.h"
 #include "chrome/common/extensions/draggable_region.h"
@@ skipping 371 matching lines @@
                      int /* channel */)
 
 // Adds a logging message to the renderer's root frame DevTools console.
 IPC_MESSAGE_ROUTED2(ExtensionMsg_AddMessageToConsole,
                     content::ConsoleMessageLevel /* level */,
                     std::string /* message */)
 
 // Notify the renderer that its window has closed.
 IPC_MESSAGE_ROUTED0(ExtensionMsg_AppWindowClosed)
 
+// Notify the renderer that an extension wants notifications when certain
+// searches match the active page.  This message replaces the old set of
+// searches, and triggers ExtensionHostMsg_OnWatchedPageChange messages from
+// each tab to keep the browser updated about changes.
+IPC_MESSAGE_CONTROL1(ExtensionMsg_WatchPages,
+                     std::vector<std::string> /* CSS selectors */)
+
 // Messages sent from the renderer to the browser.
 
 // A renderer sends this message when an extension process starts an API
 // request. The browser will always respond with a ExtensionMsg_Response.
 IPC_MESSAGE_ROUTED1(ExtensionHostMsg_Request,
                     ExtensionHostMsg_Request_Params)
 
 // A renderer sends this message when an extension process starts an API
 // request. The browser will always respond with a ExtensionMsg_Response.
 IPC_MESSAGE_CONTROL2(ExtensionHostMsg_RequestForIOThread,
@@ skipping 162 matching lines @@
 // browser process.
 IPC_SYNC_MESSAGE_CONTROL0_1(ExtensionHostMsg_GenerateUniqueID,
                             int /* unique_id */)
 
 // Resumes resource requests for a newly created app window.
 IPC_MESSAGE_CONTROL1(ExtensionHostMsg_ResumeRequests, int /* route_id */)
 
 // Sent by the renderer when the draggable regions are updated.
 IPC_MESSAGE_ROUTED1(ExtensionHostMsg_UpdateDraggableRegions,
                     std::vector<extensions::DraggableRegion> /* regions */)
+
+// Notifies the browser process that a tab has started or stopped matching
+// certain conditions.  This message is sent in response to several events:
+//
+// * ExtensionMsg_WatchPages was received, updating the set of conditions.
+// * A new page is loaded.  This will be sent after ViewHostMsg_FrameNavigate.
+//   Currently this only fires for the main frame.
+// * Something changed on an existing frame causing the set of matching searches
+//   to change.
+IPC_MESSAGE_ROUTED1(ExtensionHostMsg_OnWatchedPageChange,
+                    std::vector<std::string> /* Matching CSS selectors */)