Delete the temporary file when generating MHTML with the extension API.

chrome/renderer/resources/extensions/extension_process_bindings.js

 // Copyright (c) 2011 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.
 
 // This script contains privileged chrome extension related javascript APIs.
 // It is loaded by pages whose URL has the chrome-extension protocol.
 
 var chrome = chrome || {};
 (function() {
   native function GetExtensionAPIDefinition();
   native function StartRequest();
   native function GetChromeHidden();
   native function GetNextRequestId();
   native function Print();
 
   native function GetCurrentPageActions(extensionId);
   native function GetExtensionViews();
   native function GetNextContextMenuId();
   native function GetNextTtsEventId();
   native function OpenChannelToTab();
   native function GetRenderViewId();
   native function SetIconCommon();
   native function GetUniqueSubEventName(eventName);
   native function GetLocalFileSystem(name, path);
   native function DecodeJPEG(jpegImage);
   native function CreateBlob(filePath);
+  native function SendResponseAck(requestId);
 
   var chromeHidden = GetChromeHidden();
 
   if (!chrome)
     chrome = {};
 
   function forEach(dict, f) {
     for (key in dict) {
       if (dict.hasOwnProperty(key))
         f(key, dict[key]);
@@ skipping 134 matching lines @@
     }
     // JSON.stringify doesn't support a root object which is undefined.
     if (request.args === undefined)
       request.args = null;
 
     var sargs = opt_args.noStringify ?
         request.args : chromeHidden.JSON.stringify(request.args);
     var nativeFunction = opt_args.nativeFunction || StartRequest;
 
     var requestId = GetNextRequestId();
+    request.id = requestId;
     requests[requestId] = request;
     var hasCallback =
         (request.callback || opt_args.customCallback) ? true : false;
     return nativeFunction(functionName, sargs, requestId, hasCallback,
                           opt_args.forIOThread);
   }
 
   // --- Setup additional api's not currently handled in common/extensions/api
 
   // WebRequestEvent object. This is used for special webRequest events with
@@ skipping 568 matching lines @@
     };
 
     apiFunctions["experimental.savePage.saveAsMHTML"].customCallback =
       function(name, request, response) {
         var params = chromeHidden.JSON.parse(response);
         var path = params.mhtmlFilePath;
         var size = params.mhtmlFileLength;
 
         if (request.callback)
           request.callback(CreateBlob(path, size));
+        request.callback = null;
 
-        request.callback = null;
+        // Notify the browser. Now that the blob is referenced from JavaScript,
+        // the browser can drop its reference to it.
+        SendResponseAck(request.id);
       };
 
     apiFunctions["fileBrowserPrivate.requestLocalFileSystem"].customCallback =
       function(name, request, response) {
         var resp = response ? [chromeHidden.JSON.parse(response)] : [];
         var fs = null;
         if (!resp[0].error)
           fs = GetLocalFileSystem(resp[0].name, resp[0].path);
         if (request.callback)
           request.callback(fs);
@@ skipping 268 matching lines @@
 
   if (!chrome.tts)
     chrome.tts = {};
 
   if (!chrome.ttsEngine)
     chrome.ttsEngine = {};
 
   if (!chrome.experimental.downloads)
     chrome.experimental.downloads = {};
 })();