Backout 6de71ba24d50 (bug 922835) because it was the wrong version of the patch. r=me

toolkit/devtools/server/actors/script.js

@@ -467,13 +467,6 @@ ThreadActor.prototype = {
     return this._sources;
   },
 
-  get youngestFrame() {
-    if (!this.state == "paused") {
-      return null;
-    }
-    return this.dbg.getNewestFrame();
-  },
-
   _prettyPrintWorker: null,
   get prettyPrintWorker() {
     if (!this._prettyPrintWorker) {
@@ -1186,6 +1179,10 @@ ThreadActor.prototype = {
                message: "cannot access the environment of this frame." };
     }
 
+    // We'll clobber the youngest frame if the eval causes a pause, so
+    // save our frame now to be restored after eval returns.
+    // XXX: or we could just start using dbg.getNewestFrame() now that it
+    // works as expected.
     let youngest = this.youngestFrame;
 
     // Put ourselves back in the running state and inform the client.
@@ -1741,6 +1738,10 @@ ThreadActor.prototype = {
 
     this._state = "paused";
 
+    // Save the pause frame (if any) as the youngest frame for
+    // stack viewing.
+    this.youngestFrame = aFrame;
+
     // Create the actor pool that will hold the pause actor and its
     // children.
     dbg_assert(!this._pausePool, "No pause pool should exist yet");
@@ -4023,7 +4024,7 @@ function getOffsetColumn(aOffset, aScript) {
  *          Returns an object of the form { url, line, column }
  */
 function getFrameLocation(aFrame) {
-  if (!aFrame || !aFrame.script) {
+  if (!aFrame.script) {
     return { url: null, line: null, column: null };
   }
   return {