Further tests for bug 451286, and tidy up the relevant file somewhat. r=mano

    const Ci = Components.interfaces;

    const Cc = Components.classes;

    const Cr = Components.results;

    const SEARCH_TEXT = "text";

    const DATAURI = "data:text/html," + SEARCH_TEXT;

    var gFindBar = null;

    var gBrowser;

        gFindBar = document.getElementById("FindToolbar");

        gBrowser = document.getElementById("content");

        gBrowser.addEventListener("pageshow", onPageShow, false);

        gBrowser.loadURI("data:text/html,text<iframe style='display: none;' src='data:text/html,text'></iframe>text<iframe id='if' src='data:text/html,text'></iframe>text");

        // Bug 451286. An iframe that should be highlighted

        var visible = "<iframe id='visible' src='" + DATAURI + "'></iframe>";

        // Bug 493658. An invisible iframe that shouldn't interfere with

        // highlighting matches lying after it in the document

        var invisible = "<iframe id='invisible' style='display: none;' " +

                        "src='" + DATAURI + "'></iframe>";

        var uri = DATAURI + invisible + SEARCH_TEXT + visible + SEARCH_TEXT;

        gBrowser.loadURI(uri);

      }

      let tm = Cc["@mozilla.org/thread-manager;1"].

               getService(Ci.nsIThreadManager);

    function onPageShow() {

      gBrowser.removeEventListener("pageshow", onPageShow, false);

      // First, take a snapshot of the window without highlighting

      // to be used later to test the unhighlighting case

      var gWin = gBrowser.contentWindow;

      var noHighlightSnapshot = snapshotWindow(gWin);

      gFindBar.open();

      var search = "text";

      gFindBar._findField.value = search;

      gFindBar._findField.value = SEARCH_TEXT;

      var matchCase = gFindBar.getElement("find-case-sensitive");

      if (matchCase.checked)

        matchCase.doCommand();

      gFindBar.toggleHighlight(true);

      gFindBar.close();

      // Take snapshot

      var gWin = gBrowser.contentWindow;

      // Take snapshot of highlighing

      var findSnapshot = snapshotWindow(gWin);

      // Now, perform the same selections manually

      // Now, remove the highlighting, and take a snapshot to compare

      // to our original state

      gFindBar.open();

      gFindBar.toggleHighlight(false);

      gFindBar.close();

      var unhighlightSnapshot = snapshotWindow(gWin);

      // Select the matches that should have been highlighted manually

      var doc = gBrowser.contentDocument;

      var iframe = doc.getElementById("if");

      // Create a manual highlight in the visible iframe to test bug 451286

      var iframe = doc.getElementById("visible");

      var ifBody = iframe.contentDocument.body;

      var range = iframe.contentDocument.createRange();

      range.selectNodeContents(ifBody.childNodes[0]);

      var ifWindow = doc.getElementById("if").contentWindow;

      var ifWindow = iframe.contentWindow;

      var ifDocShell = ifWindow.QueryInterface(Ci.nsIInterfaceRequestor)

                               .getInterface(Ci.nsIWebNavigation)

                               .QueryInterface(Ci.nsIDocShell);

                                   .getInterface(Ci.nsISelectionDisplay)

                                   .QueryInterface(Ci.nsISelectionController);

      var findSelection = ifController.getSelection(ifController.SELECTION_FIND);

      findSelection.addRange(range);

      var frameFindSelection =

        ifController.getSelection(ifController.SELECTION_FIND);

      frameFindSelection.addRange(range);

      // Create manual highlights in the main document (the matches that lie

      // before/after the iframes

      var docShell = gWin.QueryInterface(Ci.nsIInterfaceRequestor)

                         .getInterface(Ci.nsIWebNavigation)

                          .QueryInterface(Ci.nsIDocShell);

                               .getInterface(Ci.nsISelectionDisplay)

                               .QueryInterface(Ci.nsISelectionController);

      var findSelection2 = controller.getSelection(ifController.SELECTION_FIND);

      var docFindSelection =

        controller.getSelection(ifController.SELECTION_FIND);

      range = doc.createRange();

      range.selectNodeContents(doc.body.childNodes[0]);

      findSelection2.addRange(range);

      docFindSelection.addRange(range);

      range = doc.createRange();

      range.selectNodeContents(doc.body.childNodes[2]);

      findSelection2.addRange(range);

      docFindSelection.addRange(range);

      range = doc.createRange();

      range.selectNodeContents(doc.body.childNodes[4]);

      findSelection2.addRange(range);

      docFindSelection.addRange(range);

      //Take snapshots

      // Take snapshot of manual highlighting

      var manualSnapshot = snapshotWindow(gBrowser.contentWindow);

      // Test 1: Were the matches in iframe correctly highlighted?

      var res = compareSnapshots(findSnapshot, manualSnapshot, true);

      ok(res[0], "Matches found in iframe correctly highlighted");

      // Test 2: Were the matches in iframe correctly unhighlighted?

      res = compareSnapshots(noHighlightSnapshot, unhighlightSnapshot, true);

      ok(res[0], "Highlighting in iframe correctly removed");

      finish();

    }

  ]]></script>