Bug 1430844: Add assertions that would've caught this. r=bz

MozReview-Commit-ID: 1UfhIRn2We2

layout/base/GeckoRestyleManager.cpp

@@ -562,6 +562,8 @@ GeckoRestyleManager::ProcessPendingRestyles()
   NS_PRECONDITION(PresContext()->Document(), "No document?  Pshaw!");
   NS_PRECONDITION(!nsContentUtils::IsSafeToRunScript(),
                   "Missing a script blocker!");
+  MOZ_ASSERT(!PresContext()->HasPendingMediaQueryUpdates(),
+             "Someone forgot to update media queries?");
 
   // First do any queued-up frame creation.  (We should really
   // merge this into the rest of the process, though; see bug 827239.)

layout/base/ServoRestyleManager.cpp

@@ -1093,13 +1093,18 @@ ServoRestyleManager::SnapshotFor(Element* aElement)
 void
 ServoRestyleManager::DoProcessPendingRestyles(ServoTraversalFlags aFlags)
 {
-  MOZ_ASSERT(PresContext()->Document(), "No document?  Pshaw!");
+  nsPresContext* presContext = PresContext();
+
+  MOZ_ASSERT(presContext->Document(), "No document?  Pshaw!");
+  MOZ_ASSERT(!presContext->HasPendingMediaQueryUpdates(),
+             "Someone forgot to update media queries?");
   MOZ_ASSERT(!nsContentUtils::IsSafeToRunScript(), "Missing a script blocker!");
   MOZ_ASSERT(!mInStyleRefresh, "Reentrant call?");
 
-  if (MOZ_UNLIKELY(!PresContext()->PresShell()->DidInitialize())) {
+
+  if (MOZ_UNLIKELY(!presContext->PresShell()->DidInitialize())) {
     // PresShell::FlushPendingNotifications doesn't early-return in the case
-    // where the PreShell hasn't yet been initialized (and therefore we haven't
+    // where the PresShell hasn't yet been initialized (and therefore we haven't
     // yet done the initial style traversal of the DOM tree). We should arguably
     // fix up the callers and assert against this case, but we just detect and
     // handle it for now.
@@ -1112,11 +1117,11 @@ ServoRestyleManager::DoProcessPendingRestyles(ServoTraversalFlags aFlags)
   AnimationsWithDestroyedFrame animationsWithDestroyedFrame(this);
 
   ServoStyleSet* styleSet = StyleSet();
-  nsIDocument* doc = PresContext()->Document();
+  nsIDocument* doc = presContext->Document();
 
   // Ensure the refresh driver is active during traversal to avoid mutating
   // mActiveTimer and mMostRecentRefresh time.
-  PresContext()->RefreshDriver()->MostRecentRefresh();
+  presContext->RefreshDriver()->MostRecentRefresh();
 
 
   // Perform the Servo traversal, and the post-traversal if required. We do this
@@ -1140,7 +1145,7 @@ ServoRestyleManager::DoProcessPendingRestyles(ServoTraversalFlags aFlags)
     // Recreate style contexts, and queue up change hints (which also handle
     // lazy frame construction).
     {
-      AutoRestyleTimelineMarker marker(mPresContext->GetDocShell(), false);
+      AutoRestyleTimelineMarker marker(presContext->GetDocShell(), false);
       DocumentStyleRootIterator iter(doc->GetServoRestyleRoot());
       while (Element* root = iter.GetNextStyleRoot()) {
         nsTArray<nsIFrame*> wrappersToRestyle;
@@ -1159,7 +1164,7 @@ ServoRestyleManager::DoProcessPendingRestyles(ServoTraversalFlags aFlags)
     // iterate until there's nothing left.
     {
       AutoTimelineMarker marker(
-        mPresContext->GetDocShell(), "StylesApplyChanges");
+        presContext->GetDocShell(), "StylesApplyChanges");
       ReentrantChangeList newChanges;
       mReentrantChanges = &newChanges;
       while (!currentChanges.IsEmpty()) {

layout/base/nsPresContext.h

@@ -223,6 +223,13 @@ public:
 
   mozilla::StyleSetHandle StyleSet() const { return GetPresShell()->StyleSet(); }
 
+#ifdef DEBUG
+  bool HasPendingMediaQueryUpdates() const
+  {
+    return mPendingMediaFeatureValuesChanged;
+  }
+#endif
+
   nsFrameManager* FrameManager()
     { return PresShell()->FrameManager(); }
 

layout/style/ServoStyleSet.cpp

@@ -1340,6 +1340,8 @@ ServoStyleSet::AppendFontFaceRules(nsTArray<nsFontFaceRuleContainer>& aArray)
 nsCSSCounterStyleRule*
 ServoStyleSet::CounterStyleRuleForName(nsAtom* aName)
 {
+  // FIXME(emilio): This should probably call UpdateStylistIfNeeded, or
+  // otherwise assert?
   return Servo_StyleSet_GetCounterStyleRule(mRawSet.get(), aName);
 }