Extensions: Send the tab id to platform apps.

chrome/renderer/resources/extensions/messaging.js

 // 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.
 
 // This contains unprivileged javascript APIs for extensions and apps.  It
 // can be loaded by any extension-related context, such as content scripts or
 // background pages. See user_script_slave.cc for script that is loaded by
 // content scripts only.
 
   // TODO(kalman): factor requiring chrome out of here.
@@ skipping 12 matching lines @@
   var kMessageChannel = "chrome.runtime.sendMessage";
   var kNativeMessageChannel = "chrome.runtime.sendNativeMessage";
 
   // Map of port IDs to port object.
   var ports = {};
 
   // Map of port IDs to unloadEvent listeners. Keep track of these to free the
   // unloadEvent listeners when ports are closed.
   var portReleasers = {};
 
+  // A stack of tabs ids for the tabs that are dispatching requests.
+  var dispatchingTabIds = [];
+
   // Change even to odd and vice versa, to get the other side of a given
   // channel.
   function getOppositePortId(portId) { return portId ^ 1; }
 
   // Port object.  Represents a connection to another script context through
   // which messages can be passed.
   function Port(portId, opt_name) {
     this.portId_ = portId;
     this.name = opt_name;
 
@@ skipping 92 matching lines @@
     if (sourceExtensionId != "" && sourceExtensionId != targetExtensionId)
       $Array.push(errorMsg, "for extension " + targetExtensionId);
     if (sourceUrl != "")
       $Array.push(errorMsg, "for URL " + sourceUrl);
     lastError.set(eventName, errorMsg.join(" ") + ").", null, chrome);
   }
 
   // Helper function for dispatchOnConnect
   function dispatchOnRequest(portId, channelName, sender,
                              sourceExtensionId, targetExtensionId, sourceUrl,
-                             isExternal) {
+                             isExternal, senderTabId) {
     var isSendMessage = channelName == kMessageChannel;
     var requestEvent = null;
     if (isSendMessage) {
       if (chrome.runtime) {
         requestEvent = isExternal ? chrome.runtime.onMessageExternal
                                   : chrome.runtime.onMessage;
       }
     } else {
       if (chrome.extension) {
         requestEvent = isExternal ? chrome.extension.onRequestExternal
@@ skipping 23 matching lines @@
       // In case the extension never invokes the responseCallback, and also
       // doesn't keep a reference to it, we need to clean up the port. Do
       // so by attaching to the garbage collection of the responseCallback
       // using some native hackery.
       messagingNatives.BindToGC(responseCallback, function() {
         if (port) {
           port.destroy_();
           port = null;
         }
       });
+      if (senderTabId)
+        dispatchingTabIds.push(senderTabId);
       var rv = requestEvent.dispatch(request, sender, responseCallback);
+      if (senderTabId)
+        dispatchingTabIds.pop();
+
       if (isSendMessage) {
         responseCallbackPreserved =
             rv && rv.results && $Array.indexOf(rv.results, true) > -1;
         if (!responseCallbackPreserved && port) {
           // If they didn't access the response callback, they're not
           // going to send a response, so clean up the port immediately.
           port.destroy_();
           port = null;
         }
       }
@@ skipping 13 matching lines @@
     return true;
   }
 
   // Called by native code when a channel has been opened to this context.
   function dispatchOnConnect(portId,
                              channelName,
                              sourceTab,
                              sourceExtensionId,
                              targetExtensionId,
                              sourceUrl,
                              tlsChannelId) {

[not at google - send to devlin, 2014/01/23 16:41:59]

you could pass the isPlatformApp flag in here and save having to store it in the
sourceTab structure (you can retrieve it from the extension() value when you run
the dispatchOnConnect function from messaging_natives.cc)

     // Only create a new Port if someone is actually listening for a connection.
     // In addition to being an optimization, this also fixes a bug where if 2
     // channels were opened to and from the same process, closing one would
     // close both.
     var extensionId = processNatives.GetExtensionId();
     if (targetExtensionId != extensionId)
       return false;  // not for us
 
     if (ports[getOppositePortId(portId)])
       return false;  // this channel was opened by us, so ignore it
 
     // Determine whether this is coming from another extension, so we can use
     // the right event.
     var isExternal = sourceExtensionId != extensionId;
 
     var sender = {};
     if (sourceExtensionId != '')
       sender.id = sourceExtensionId;
     if (sourceUrl)
       sender.url = sourceUrl;
-    if (sourceTab)
+    if (sourceTab && !('isPlatformApp' in sourceTab))
       sender.tab = sourceTab;
     if (tlsChannelId !== undefined)
       sender.tlsChannelId = tlsChannelId;
 
     // Special case for sendRequest/onRequest and sendMessage/onMessage.
     if (channelName == kRequestChannel || channelName == kMessageChannel) {
+      var senderTabId =
+          (sourceTab && ('id' in sourceTab) && ('isPlatformApp' in sourceTab)) ?
+              sourceTab['id'] : null;
       return dispatchOnRequest(portId, channelName, sender,
                                sourceExtensionId, targetExtensionId, sourceUrl,
-                               isExternal);
+                               isExternal, senderTabId);

[not at google - send to devlin, 2014/01/23 16:41:59]

The above comment said... maybe it would be easier to implement this from C++
similar to
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/renderer/ex...
-- you'd need to define your own ScopedSenderTabID type or something, but I'd
feel more confident that it was correct. Changing this JS file is scary, it's
had so many subtle bugs over its time. If you do that in C++ then I'm not even
sure you need to change any JS.

     }
 
     var connectEvent = null;
     if (chrome.runtime) {
       connectEvent = isExternal ? chrome.runtime.onConnectExternal
                                 : chrome.runtime.onConnect;
     }
     if (!connectEvent)
       return false;
     if (!connectEvent.hasListeners())
@@ skipping 89 matching lines @@
   function sendMessageUpdateArguments(functionName, hasOptionsArgument) {
     // skip functionName and hasOptionsArgument
     var args = $Array.slice(arguments, 2);
     var alignedArgs = messagingUtils.alignSendMessageArguments(args,
         hasOptionsArgument);
     if (!alignedArgs)
       throw new Error('Invalid arguments to ' + functionName + '.');
     return alignedArgs;
   }
 
+  function currentTabId() {
+    return dispatchingTabIds[dispatchingTabIds.length - 1];
+  }
+
 exports.kRequestChannel = kRequestChannel;
 exports.kMessageChannel = kMessageChannel;
 exports.kNativeMessageChannel = kNativeMessageChannel;
 exports.Port = Port;
 exports.createPort = createPort;
 exports.sendMessageImpl = sendMessageImpl;
 exports.sendMessageUpdateArguments = sendMessageUpdateArguments;
+exports.currentTabId = currentTabId;
 
 // For C++ code to call.
 exports.hasPort = hasPort;
 exports.dispatchOnConnect = dispatchOnConnect;
 exports.dispatchOnDisconnect = dispatchOnDisconnect;
 exports.dispatchOnMessage = dispatchOnMessage;