Extensions: Send the tab id to platform apps.

chrome/renderer/resources/extensions/messaging.js

Index: chrome/renderer/resources/extensions/messaging.js
===================================================================
--- chrome/renderer/resources/extensions/messaging.js	(revision 246436)
+++ chrome/renderer/resources/extensions/messaging.js	(working copy)
@@ -30,6 +30,9 @@
   // 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; }
@@ -142,7 +145,7 @@
   // Helper function for dispatchOnConnect
   function dispatchOnRequest(portId, channelName, sender,
                              sourceExtensionId, targetExtensionId, sourceUrl,
-                             isExternal) {
+                             isExternal, senderTabId) {
     var isSendMessage = channelName == kMessageChannel;
     var requestEvent = null;
     if (isSendMessage) {
@@ -186,7 +189,12 @@
           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;
@@ -241,16 +249,19 @@
       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;
@@ -360,6 +371,10 @@
     return alignedArgs;
   }
 
+  function currentTabId() {
+    return dispatchingTabIds[dispatchingTabIds.length - 1];
+  }
+
 exports.kRequestChannel = kRequestChannel;
 exports.kMessageChannel = kMessageChannel;
 exports.kNativeMessageChannel = kNativeMessageChannel;
@@ -367,6 +382,7 @@
 exports.createPort = createPort;
 exports.sendMessageImpl = sendMessageImpl;
 exports.sendMessageUpdateArguments = sendMessageUpdateArguments;
+exports.currentTabId = currentTabId;
 
 // For C++ code to call.
 exports.hasPort = hasPort;