Issue 1739 - Respect MessageSender.frameId if available

chrome/ext/background.js

Index: chrome/ext/background.js
===================================================================
--- a/chrome/ext/background.js
+++ b/chrome/ext/background.js
@@ -358,10 +358,21 @@
           if (!frames)
             return null;
 
-          for (var frameId in frames)
+          if ("frameId" in rawSender)
           {
-            if (frames[frameId].url == rawSender.url)
-              return frames[frameId].parent;
+            // Chrome 41+
+            var frame = frames[rawSender.frameId];
+            if (frame)
+              return frame.parent;
+          }
+          else

[kzar, 2015/01/05 15:30:15]

Maybe remove the else here? That way if rawSender.frameId exists but
frames[rawSender.frameId] doesn't we could still use the old approach?

[Sebastian Noack, 2015/01/05 15:33:36]

I think falling back to the top-level frame in this case is fine. Note, that
whatever frame we would find (if any) with the old approach would be the wrong
frame anyway, if we don't know the actual frame.

+          {
+            // Chrome 28-40
+            for (var frameId in frames)
+            {
+              if (frames[frameId].url == rawSender.url)
+                return frames[frameId].parent;
+            }
           }
 
           return frames[0];