Bug 875157 (part 2) - prevent background thumbnails from displaying alerts/dialogs. r=adw

toolkit/components/prompts/src/nsPrompter.js

@@ -365,13 +365,28 @@ XPCOMUtils.defineLazyGetter(PromptUtils, "ellipsis", function () {
 
 
 function openModalWindow(domWin, uri, args) {
-    // XXX Investigate supressing modal state when we're called without a
-    // window? Seems odd to affect whatever window happens to be active.
-    if (!domWin)
+    // There's an implied contract that says modal prompts should still work
+    // when no "parent" window is passed for the dialog (eg, the "Master
+    // Password" dialog does this).  These prompts must be shown even if there
+    // are *no* visible windows at all.
+    // There's also a requirement for prompts to be blocked if a window is
+    // passed and that window is hidden (eg, auth prompts are supressed if the
+    // passed window is the hidden window).
+    // See bug 875157 comment 30 for more...
+    if (domWin) {
+        // a domWin was passed, so we can apply the check for it being hidden.
+        let winUtils = domWin.QueryInterface(Ci.nsIInterfaceRequestor)
+                             .getInterface(Ci.nsIDOMWindowUtils);
+        if (!winUtils.isParentWindowMainWidgetVisible) {
+            throw Components.Exception("Cannot call openModalWindow on a hidden window",
+                                       Cr.NS_ERROR_NOT_AVAILABLE);
+        }
+    } else {
+        // We try and find a window to use as the parent, but don't consider
+        // if that is visible before showing the prompt.
         domWin = Services.ww.activeWindow;
-
-    // domWin may still be null here if there are _no_ windows open.
-
+        // domWin may still be null here if there are _no_ windows open.
+    }
     // Note that we don't need to fire DOMWillOpenModalDialog and
     // DOMModalDialogClosed events here, wwatcher's OpenWindowInternal
     // will do that. Similarly for enterModalState / leaveModalState.

toolkit/components/thumbnails/content/backgroundPageThumbsContent.js

@@ -11,6 +11,13 @@ Cu.import("resource://gre/modules/PageThumbs.jsm");
 const backgroundPageThumbsContent = {
 
   init: function () {
+    // Arrange to prevent (most) popup dialogs for this window - popups done
+    // in the parent (eg, auth) aren't prevented, but alert() etc are.
+    let dwu = content.
+                QueryInterface(Ci.nsIInterfaceRequestor).
+                getInterface(Ci.nsIDOMWindowUtils);
+    dwu.preventFurtherDialogs();
+
     // Stop about:blank from loading.  If it finishes loading after a capture
     // request is received, it could trigger the capture's load listener.
     this._webNav.stop(Ci.nsIWebNavigation.STOP_NETWORK);

toolkit/components/thumbnails/test/browser_thumbnails_background.js

@@ -227,10 +227,43 @@ let tests = [
       isnot([r, g, b].toString(), [0, 255, 0].toString(),
             "The captured page should not be green.");
       gBrowser.removeTab(tab);
+      file.remove(false);
       deferred.resolve();
     });
     yield deferred.promise;
   },
+
+  // the following tests attempt to display modal dialogs.  The test just
+  // relies on the fact that if the dialog was displayed the test will hang
+  // and timeout.  IOW - the tests would pass if the dialogs appear and are
+  // manually closed by the user - so don't do that :)  (obviously there is
+  // noone available to do that when run via tbpl etc, so this should be safe,
+  // and it's tricky to use the window-watcher to check a window *does not*
+  // appear - how long should the watcher be active before assuming it's not
+  // going to appear?)
+  function noAuthPrompt() {
+    let url = "http://mochi.test:8888/browser/browser/base/content/test/authenticate.sjs?user=anyone";
+    let file = fileForURL(url);
+    ok(!file.exists(), "Thumbnail file should not already exist.");
+
+    let capturedURL = yield capture(url);
+    is(capturedURL, url, "Captured URL should be URL passed to capture.");
+    ok(file.exists(),
+       "Thumbnail file should exist even though it requires auth.");
+    file.remove(false);
+  },
+
+  function noAlert() {
+    let url = "data:text/html,<script>alert('yo!');</script>";
+    let file = fileForURL(url);
+    ok(!file.exists(), "Thumbnail file should not already exist.");
+
+    let capturedURL = yield capture(url);
+    is(capturedURL, url, "Captured URL should be URL passed to capture.");
+    ok(file.exists(),
+       "Thumbnail file should exist even though it alerted.");
+    file.remove(false);
+  },
 ];
 
 function capture(url, options) {