Bug 729162 - Add per-docshell privacy mode transition observers. r=bz

docshell/base/Makefile.in

@@ -83,6 +83,7 @@ XPIDLSRCS = \
   nsIRefreshURI.idl \
   nsIContentViewerContainer.idl \
   nsIDocumentLoaderFactory.idl \
+  nsIPrivacyTransitionObserver.idl \
   $(NULL)
 
 EXPORTS = \

docshell/base/nsDocShell.cpp

@@ -107,6 +107,7 @@
 #include "nsIScriptChannel.h"
 #include "nsIOfflineCacheUpdate.h"
 #include "nsITimedChannel.h"
+#include "nsIPrivacyTransitionObserver.h"
 #include "nsCPrefetchService.h"
 #include "nsJSON.h"
 #include "IHistory.h"
@@ -2041,7 +2042,8 @@ nsDocShell::GetUsePrivateBrowsing(bool* aUsePrivateBrowsing)
 NS_IMETHODIMP
 nsDocShell::SetUsePrivateBrowsing(bool aUsePrivateBrowsing)
 {
-    if (aUsePrivateBrowsing != mInPrivateBrowsing) {
+    bool changed = aUsePrivateBrowsing != mInPrivateBrowsing;
+    if (changed) {
         mInPrivateBrowsing = aUsePrivateBrowsing;
         if (aUsePrivateBrowsing) {
             IncreasePrivateDocShellCount();
@@ -2057,9 +2059,32 @@ nsDocShell::SetUsePrivateBrowsing(bool aUsePrivateBrowsing)
             shell->SetUsePrivateBrowsing(aUsePrivateBrowsing);
         }
     }
+
+    if (changed) {
+        nsTObserverArray<nsWeakPtr>::ForwardIterator iter(mPrivacyObservers);
+        while (iter.HasMore()) {
+            nsWeakPtr ref = iter.GetNext();
+            nsCOMPtr<nsIPrivacyTransitionObserver> obs = do_QueryReferent(ref);
+            if (!obs) {
+                mPrivacyObservers.RemoveElement(ref);
+            } else {
+                obs->PrivateModeChanged(aUsePrivateBrowsing);
+            }
+        }
+    }
     return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDocShell::AddWeakPrivacyTransitionObserver(nsIPrivacyTransitionObserver* aObserver)
+{
+    nsWeakPtr weakObs = do_GetWeakReference(aObserver);
+    if (!weakObs) {
+        return NS_ERROR_NOT_AVAILABLE;
+    }
+    return mPrivacyObservers.AppendElement(weakObs) ? NS_OK : NS_ERROR_FAILURE;
+}
+
 NS_IMETHODIMP nsDocShell::GetAllowMetaRedirects(bool * aReturn)
 {
     NS_ENSURE_ARG_POINTER(aReturn);

docshell/base/nsDocShell.h

@@ -847,6 +847,7 @@ protected:
 private:
     nsCOMPtr<nsIAtom> mForcedCharset;
     nsCOMPtr<nsIAtom> mParentCharset;
+    nsTObserverArray<nsWeakPtr> mPrivacyObservers;
     PRInt32          mParentCharsetSource;
 
 #ifdef DEBUG

docshell/base/nsIDocShell.idl

@@ -71,8 +71,9 @@ interface nsIDOMStorage;
 interface nsIPrincipal;
 interface nsIWebBrowserPrint;
 interface nsIVariant;
+interface nsIPrivacyTransitionObserver;
 
-[scriptable, uuid(c7325422-817e-4321-957a-c0bdd764941d)]
+[scriptable, uuid(6f60ac96-fa2c-41a5-92b4-29aaadbd7a7b)]
 interface nsIDocShell : nsISupports
 {
   /**
@@ -603,6 +604,12 @@ interface nsIDocShell : nsISupports
    */
   attribute PRInt32 parentCharsetSource;
 
+  /**
+   * Add an observer to the list of parties to be notified when this docshell's
+   * private browsing status is changed. |obs| must support weak references.
+   */
+  void addWeakPrivacyTransitionObserver(in nsIPrivacyTransitionObserver obs);
+
   /*
    * Is this docshell a browser frame (i.e., does it correspond to an <iframe
    * mozbrowser>)?  The frameloader is responsible for setting this property

docshell/base/nsIPrivacyTransitionObserver.idl

@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[scriptable, function, uuid(b4b1449d-0ef0-47f5-b62e-adc57fd49702)]
+interface nsIPrivacyTransitionObserver : nsISupports
+{
+  void privateModeChanged(in bool enabled);
+};

docshell/test/unit/test_privacy_transition.js

@@ -0,0 +1,23 @@
+var gNotifications = 0;
+
+var observer = {
+  QueryInterface: function(iid) {
+    if (Ci.nsIPrivacyTransitionObserver.equals(iid) ||
+        Ci.nsISupportsWeakReference.equals(iid) ||
+        Ci.nsISupports.equals(iid))
+      return this;
+    throw Cr.NS_ERROR_NO_INTERFACE;
+  },
+  
+  privateModeChanged: function(enabled) {
+    gNotifications++;
+  }
+}
+
+function run_test() {
+  var docshell = Cc["@mozilla.org/docshell;1"].createInstance(Ci.nsIDocShell);
+  docshell.addWeakPrivacyTransitionObserver(observer);
+  docshell.QueryInterface(Ci.nsILoadContext).usePrivateBrowsing = true;
+  docshell.QueryInterface(Ci.nsILoadContext).usePrivateBrowsing = false;
+  do_check_eq(gNotifications, 2);
+}

docshell/test/unit/xpcshell.ini

@@ -6,3 +6,4 @@ tail =
 [test_bug442584.js]
 [test_nsIDownloadHistory.js]
 [test_pb_notification.js]
+[test_privacy_transition.js]