[WORK_IN_PROGRESS] PDF::Save() fix for out-of-process-pdf.

chrome/browser/resources/pdf/background.js

 // Copyright 2013 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.
 
 (function() {
   'use strict';
 
-  /**
-   * Keep a stack of stream details for requests. These are pushed onto the
-   * stack as requests come in and popped off the stack as they are handled by a
-   * renderer.
-   * TODO(raymes): This is probably racy for multiple requests. We could
-   * associate an ID with the request but this code will probably change
-   * completely when MIME type handling is improved.
-   */
-  var streamsCache = [];
+  var streams = {};
+  var pluginInitFunctions = {};
 
+  function flush(viewId) {
+    if (viewId in streams && viewId in pluginInitFunctions) {
+      pluginInitFunctions[viewId](streams[viewId]);
+      delete streams[viewId];
+      delete pluginInitFunctions[viewId];
+    }
+  }
+
+  // Legacy.
   window.popStreamDetails = function() {
-    if (streamsCache.length > 0)
-      return streamsCache.pop();
+    for (var viewId in streams) {
+      var result = streams[viewId];
+      delete streams[viewId];
+      delete pluginInitFunctions[viewId];
+      return result;
+    }
   };
 
   chrome.streamsPrivate.onExecuteMimeTypeHandler.addListener(
     function(streamDetails) {
-      // TODO(raymes): Currently this doesn't work with embedded PDFs (it
-      // causes the entire frame to navigate). Also work out how we can
-      // mask the URL with the URL of the PDF.
-      streamsCache.push(streamDetails);
-      chrome.tabs.update(streamDetails.tabId, {url: 'index.html'});
+      if (!streamDetails.viewId) {
+        streams.push(streamDetails);
+        chrome.tabs.update(streamDetails.tabId, {url: 'index.html'});
+      } else {
+        streams[streamDetails.viewId] = streamDetails;
+        flush(streamDetails.viewId);
+      }
     }
   );
 
+  chrome.runtime.onMessage.addListener(
+    function(request, sender, responseFunction) {
+      pluginInitFunctions[request.viewId] = responseFunction;
+      flush(request.viewId);
+    }
+  );
 }());