Make sure to flush out the content model before processing restyles; otherwise

we can end up with odd content duplication.  Bug 309986, r+sr=dbaron

content/html/document/src/nsHTMLContentSink.cpp

@@ -3977,10 +3977,20 @@ HTMLContentSink::BeginUpdate(nsIDocument *aDocument, nsUpdateType aUpdateType)
   // notification to occur. Since this could result in frame
   // creation, make sure we've flushed everything before we
   // continue.
-  // Also increment mInNotification to make sure we don't flush again
-  // until the end of this update, even if nested updates or
+
+  // Note that UPDATE_CONTENT_STATE notifications never cause
+  // synchronous frame construction, so we never have to worry about
+  // them here.  The code that handles the async event these
+  // notifications post will flush us out if it needs to.
+
+  // Also, if this is not an UPDATE_CONTENT_STATE notification,
+  // increment mInNotification to make sure we don't flush again until
+  // the end of this update, even if nested updates or
   // FlushPendingNotifications calls happen during it.
-  if (!mInNotification++ && mCurrentContext) {
+  NS_ASSERTION(aUpdateType && (aUpdateType & UPDATE_ALL) == aUpdateType,
+               "Weird update type bitmask");
+  if (aUpdateType != UPDATE_CONTENT_STATE && !mInNotification++ &&
+      mCurrentContext) {
     mCurrentContext->FlushTags(PR_TRUE);
   }
 }
@@ -3992,8 +4002,13 @@ HTMLContentSink::EndUpdate(nsIDocument *aDocument, nsUpdateType aUpdateType)
   // something else in the script processing caused the
   // notification to occur. Update our notion of how much
   // has been flushed to include any new content if ending
-  // this update leaves us not inside a notification.
-  if (!--mInNotification) {
+  // this update leaves us not inside a notification.  Note that we
+  // exclude UPDATE_CONTENT_STATE notifications here, since those
+  // never affect the frame model directly while inside the
+  // notification.
+  NS_ASSERTION(aUpdateType && (aUpdateType & UPDATE_ALL) == aUpdateType,
+               "Weird update type bitmask");
+  if (aUpdateType != UPDATE_CONTENT_STATE && !--mInNotification) {
     UpdateAllContexts();
   }
 }

layout/base/nsCSSFrameConstructor.cpp

@@ -10425,16 +10425,19 @@ nsCSSFrameConstructor::DoContentStateChanged(nsIContent* aContent,
   NS_ASSERTION(styleSet, "couldn't get style set");
 
   if (aContent) {
-    nsChangeHint hint;
-    if (aStateMask & (NS_EVENT_STATE_BROKEN | NS_EVENT_STATE_USERDISABLED |
-                      NS_EVENT_STATE_SUPPRESSED)) {
-      // Any change to a content state that affects which frames we
-      // construct must lead to a frame reconstruct here
-      hint = nsChangeHint_ReconstructFrame;
-    } else {
-      hint = NS_STYLE_HINT_NONE;
-      nsIFrame* primaryFrame = mPresShell->GetPrimaryFrameFor(aContent);
-      if (primaryFrame) {
+    nsChangeHint hint = NS_STYLE_HINT_NONE;
+    // Any change to a content state that affects which frames we construct
+    // must lead to a frame reconstruct here if we already have a frame.
+    // Note that we never decide through non-CSS means to not create frames
+    // based on content states, so if we already don't have a frame we don't
+    // need to force a reframe -- if it's needed, the HasStateDependentStyle
+    // call will handle things.
+    nsIFrame* primaryFrame = mPresShell->GetPrimaryFrameFor(aContent);
+    if (primaryFrame) {
+      if (aStateMask & (NS_EVENT_STATE_BROKEN | NS_EVENT_STATE_USERDISABLED |
+                        NS_EVENT_STATE_SUPPRESSED)) {
+        hint = nsChangeHint_ReconstructFrame;
+      } else {          
         PRUint8 app = primaryFrame->GetStyleDisplay()->mAppearance;
         if (app) {
           nsITheme *theme = presContext->GetTheme();
@@ -13253,7 +13256,16 @@ void nsCSSFrameConstructor::RestyleEvent::HandleEvent() {
   NS_ASSERTION(viewManager, "Must have view manager for update");
 
   viewManager->BeginUpdateViewBatch();
+  // Force flushing of any pending content notifications that might have queued
+  // up while our event was pending.  That will ensure that we don't construct
+  // frames for content right now that's still waiting to be notified on,
+  constructor->mPresShell->GetDocument()->
+    FlushPendingNotifications(Flush_ContentAndNotify);
+
+  // Make sure that any restyles that happen from now on will go into
+  // a new event.
   constructor->mRestyleEventQueue = nsnull;
+
   constructor->ProcessPendingRestyles();
   viewManager->EndUpdateViewBatch(NS_VMREFRESH_NO_SYNC);
 }