Bug 1336863: Flush stylesheets in RestyleForCSSRuleChanges if not under an update. r=heycam

This also moves the NoteStyleSheetsChanged to RecordStylesheetChange, which
makes more sense, and stopped special-casing author styles, since it's not
needed now.

MozReview-Commit-ID: 9WKFa0JxqlU

--HG--
extra : rebase_source : 5803620c98309bd2fbb542158e69ef3ddcee9a4b

layout/base/PresShell.cpp

@@ -4559,19 +4559,6 @@ nsIPresShell::RestyleForCSSRuleChanges()
     mPresContext->RebuildCounterStyles();
   }
 
-  // Tell Servo that the contents of style sheets have changed.
-  //
-  // NB: It's important to do so before bailing out.
-  //
-  // Even if we have no frames, we can end up styling those when creating
-  // them, and it's important for Servo to know that it needs to use the
-  // correct styles.
-  // We don't do this notification if author styles are disabled, because
-  // the ServoStyleSet has already taken care of it.
-  if (mStyleSet->IsServo() && !mStyleSet->AsServo()->GetAuthorStyleDisabled()) {
-    mStyleSet->AsServo()->NoteStyleSheetsChanged();
-  }
-
   Element* root = mDocument->GetRootElement();
   if (!mDidInitialize) {
     // Nothing to do here, since we have no frames yet
@@ -4608,6 +4595,11 @@ PresShell::RecordStyleSheetChange(StyleSheet* aStyleSheet)
   if (mStylesHaveChanged)
     return;
 
+  // Tell Servo that the contents of style sheets have changed.
+  if (ServoStyleSet* set = mStyleSet->GetAsServo()) {
+    set->NoteStyleSheetsChanged();
+  }
+
   if (aStyleSheet->IsGecko()) {
     // XXXheycam ServoStyleSheets don't support <style scoped> yet.
     Element* scopeElement = aStyleSheet->AsGecko()->GetScopeElement();

layout/style/ServoStyleSet.cpp

@@ -143,10 +143,12 @@ ServoStyleSet::SetAuthorStyleDisabled(bool aStyleDisabled)
   // call flush directly, since the PresShell won't.
   if (mAuthorStyleDisabled) {
     NoteStyleSheetsChanged();
-    Servo_StyleSet_FlushStyleSheets(mRawSet.get());
   }
   // If we've just enabled, then PresShell will trigger the notification and
   // later flush when the stylesheet objects are enabled in JS.
+  //
+  // TODO(emilio): Users can have JS disabled, can't they? Will that affect that
+  // notification on content documents?
 
   return NS_OK;
 }
@@ -838,6 +840,9 @@ void
 ServoStyleSet::NoteStyleSheetsChanged()
 {
   Servo_StyleSet_NoteStyleSheetsChanged(mRawSet.get(), mAuthorStyleDisabled);
+  if (!mBatching) {
+    Servo_StyleSet_FlushStyleSheets(mRawSet.get());
+  }
 }
 
 #ifdef DEBUG