Bug 1164693 - Part 2: Frames in a non-bidi paragraph with newline shouldn't be marked as bidi. r=smontagu

layout/base/nsBidiPresUtils.cpp

@@ -734,31 +734,44 @@ nsBidiPresUtils::ResolveParagraph(nsBlockFrame* aBlockFrame,
 #endif
 #endif
 
-  if (runCount == 1 && frameCount == 1 &&
+  bool isNonBidi = false;
+
+  nsIFrame* frame0 = frameCount > 0 ? aBpd->FrameAt(0) : nullptr;
+  nsIFrame* frame1 = frameCount > 1 ? aBpd->FrameAt(1) : nullptr;
+
+  // Non-bidi frames
+  if (runCount == 1 && (frameCount == 1 || frameCount == 2) &&
       aBpd->mParagraphDepth == 0 && aBpd->GetDirection() == NSBIDI_LTR &&
-      aBpd->GetParaLevel() == 0) {
-    // We have a single left-to-right frame in a left-to-right paragraph,
+      aBpd->GetParaLevel() == 0 &&
+      frame0 != NS_BIDI_CONTROL_FRAME &&
+      !frame0->Properties().Get(nsIFrame::EmbeddingLevelProperty()) &&
+      !frame0->Properties().Get(nsIFrame::BaseLevelProperty())) {
+    // We have a left-to-right frame in a left-to-right paragraph,
     // without bidi isolation from the surrounding text.
-    // Make sure that the embedding level and base level frame properties aren't
+    // The embedding level and base level frame properties aren't
     // set (because if they are this frame used to have some other direction,
-    // so we can't do this optimization), and we're done.
-    nsIFrame* frame = aBpd->FrameAt(0);
-    if (frame != NS_BIDI_CONTROL_FRAME &&
-        !frame->Properties().Get(nsIFrame::EmbeddingLevelProperty()) &&
-        !frame->Properties().Get(nsIFrame::BaseLevelProperty())) {
+    // so we can't do this optimization)
+    // As long as this is the only frame, or it's followed by a linebreak,
+    // this is a non-bidi paragraph.
+    if (!frame1 || (frame1 != NS_BIDI_CONTROL_FRAME &&
+                    frame1->GetType() == nsGkAtoms::brFrame)) {
+      isNonBidi = true;
+    }
+  }
+
+  if (isNonBidi) {
 #ifdef DEBUG
 #ifdef NOISY_BIDI
-      printf("early return for single direction frame %p\n", (void*)frame);
+    printf("early return for single direction frame %p\n", (void*)frame);
 #endif
 #endif
-      frame->AddStateBits(NS_FRAME_IS_BIDI);
-      return NS_OK;
-    }
+    return NS_OK;
   }
 
   nsIFrame* firstFrame = nullptr;
   nsIFrame* lastFrame = nullptr;
 
+  // Bidi frames
   for (; ;) {
     if (fragmentLength <= 0) {
       // Get the next frame from mLogicalFrames