Introduce runtime.onSuspendCanceled() event.

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/extension.h"
@@ skipping 268 matching lines @@
 IPC_MESSAGE_CONTROL2(ExtensionMsg_ShouldUnload,
                      std::string /* extension_id */,
                      int /* sequence_id */)
 
 // If we complete a round of ShouldUnload->ShouldUnloadAck messages without the
 // lazy background page becoming active again, we are ready to unload. This
 // message tells the page to dispatch the unload event.
 IPC_MESSAGE_CONTROL1(ExtensionMsg_Unload,
                      std::string /* extension_id */)
 
+// The browser changed its mind about unloading this extension.
+IPC_MESSAGE_CONTROL1(ExtensionMsg_CancelUnload,
+                     std::string /* extension_id */)
+
 // Send to renderer once the installation mentioned on
 // ExtensionHostMsg_InlineWebstoreInstall is complete.
 IPC_MESSAGE_ROUTED3(ExtensionMsg_InlineWebstoreInstallResponse,
                     int32 /* install id */,
                     bool /* whether the install was successful */,
                     std::string /* error */)
 
 // Response to the renderer for ExtensionHostMsg_GetAppNotifyChannel.
 IPC_MESSAGE_ROUTED3(ExtensionMsg_GetAppNotifyChannelResponse,
                     std::string /* channel_id */,
@@ skipping 191 matching lines @@
 // alive.
 IPC_MESSAGE_ROUTED0(ExtensionHostMsg_DecrementLazyKeepaliveCount)
 
 // Fetches a globally unique ID (for the lifetime of the browser) from the
 // 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 */)