Blobs: Catching browser-process created Blobs in extension code.

extensions/common/extension_messages.h

 // 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.
 
 // IPC messages for extensions.
 // Multiply-included message file, hence no include guard.
 
 #include <string>
 #include <vector>
 
@@ skipping 437 matching lines @@
 // 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 */)
 
+// Send by the browser to indicate a Blob handle has been transferred to the
+// renderer. This is sent after the actual extension response, and depends on
+// the sequential nature of IPCs so that the blob has already been caught.
+// This is a separate control message, so that the renderer process will send
+// an acknowledgement even if the RenderView has closed or navigated away.
+IPC_MESSAGE_CONTROL1(ExtensionMsg_TransferBlobs,
+                     std::vector<std::string> /* blob_uuids */)
+
 // 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 167 matching lines @@
 // 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
 //   FrameHostMsg_DidCommitProvisionalLoad. 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 */)
+
+// Sent by the renderer when it has received a Blob handle from the browser.
+IPC_MESSAGE_CONTROL1(ExtensionHostMsg_TransferBlobsAck,
+                     std::vector<std::string> /* blob_uuids */)