--- a/layout/generic/nsLineLayout.cpp
+++ b/layout/generic/nsLineLayout.cpp
@@ -248,16 +248,31 @@ nsLineLayout::BeginLineReflow(nscoord aI
 
     psd->mICoord += indent;
   }
 
   PerFrameData* pfd = NewPerFrameData(mBlockReflowState->frame);
   pfd->mAscent = 0;
   pfd->mSpan = psd;
   psd->mFrame = pfd;
+  nsIFrame* frame = mBlockReflowState->frame;
+  if (frame->GetType() == nsGkAtoms::rubyTextContainerFrame) {
+    // Ruby text container won't be reflowed via ReflowFrame, hence the
+    // relative positioning information should be recorded here.
+    MOZ_ASSERT(mBaseLineLayout != this);
+    pfd->mRelativePos =
+      mBlockReflowState->mStyleDisplay->IsRelativelyPositionedStyle();
+    if (pfd->mRelativePos) {
+      MOZ_ASSERT(
+        mBlockReflowState->GetWritingMode() == frame->GetWritingMode(),
+        "mBlockReflowState->frame == frame, "
+        "hence they should have identical writing mode");
+      pfd->mOffsets = mBlockReflowState->ComputedLogicalOffsets();
+    }
+  }
 }
 
 void
 nsLineLayout::EndLineReflow()
 {
 #ifdef NOISY_REFLOW
   nsFrame::ListTag(stdout, mBlockReflowState->frame);
   printf(": EndLineReflow: width=%d\n", mRootSpan->mICoord - mRootSpan->mIStart);
@@ -670,16 +685,17 @@ nsLineLayout::NewPerFrameData(nsIFrame* 
   pfd->mIsBullet = false;
   pfd->mSkipWhenTrimmingWhitespace = false;
   pfd->mIsEmpty = false;
   pfd->mIsLinkedToBase = false;
 
   WritingMode frameWM = aFrame->GetWritingMode();
   WritingMode lineWM = mRootSpan->mWritingMode;
   pfd->mBounds = LogicalRect(lineWM);
+  pfd->mOverflowAreas.Clear();
   pfd->mMargin = LogicalMargin(lineWM);
   pfd->mBorderPadding = LogicalMargin(lineWM);
   pfd->mOffsets = LogicalMargin(frameWM);
 
   pfd->mJustificationInfo = JustificationInfo();
   pfd->mJustificationAssignment = JustificationAssignment();
 
 #ifdef DEBUG
@@ -3035,16 +3051,36 @@ nsLineLayout::ApplyRelativePositioning(P
   // right and bottom are handled by
   // nsHTMLReflowState::ComputeRelativeOffsets
   nsHTMLReflowState::ApplyRelativePositioning(frame, frameWM,
                                               aPFD->mOffsets, &origin,
                                               mContainerWidth);
   frame->SetPosition(frameWM, origin, mContainerWidth);
 }
 
+// This method do relative positioning for ruby annotations.
+void
+nsLineLayout::RelativePositionAnnotations(PerSpanData* aRubyPSD,
+                                          nsOverflowAreas& aOverflowAreas)
+{
+  MOZ_ASSERT(aRubyPSD->mFrame->mFrame->GetType() == nsGkAtoms::rubyFrame);
+  for (PerFrameData* pfd = aRubyPSD->mFirstFrame; pfd; pfd = pfd->mNext) {
+    MOZ_ASSERT(pfd->mFrame->GetType() == nsGkAtoms::rubyBaseContainerFrame);
+    for (PerFrameData* rtc = pfd->mNextAnnotation;
+         rtc; rtc = rtc->mNextAnnotation) {
+      nsIFrame* rtcFrame = rtc->mFrame;
+      MOZ_ASSERT(rtcFrame->GetType() == nsGkAtoms::rubyTextContainerFrame);
+      ApplyRelativePositioning(rtc);
+      nsOverflowAreas rtcOverflowAreas;
+      RelativePositionFrames(rtc->mSpan, rtcOverflowAreas);
+      aOverflowAreas.UnionWith(rtcOverflowAreas + rtcFrame->GetPosition());
+    }
+  }
+}
+
 void
 nsLineLayout::RelativePositionFrames(PerSpanData* psd, nsOverflowAreas& aOverflowAreas)
 {
   nsOverflowAreas overflowAreas;
   WritingMode wm = psd->mWritingMode;
   if (psd != mRootSpan) {
     // The span's overflow areas come in three parts:
     // -- this frame's width and height
@@ -3129,16 +3165,21 @@ nsLineLayout::RelativePositionFrames(Per
       nsContainerFrame::SyncFrameViewAfterReflow(mPresContext, frame,
                                                  frame->GetView(),
                                                  r.VisualOverflow(),
                                                  NS_FRAME_NO_MOVE_VIEW);
 
     overflowAreas.UnionWith(r + frame->GetPosition());
   }
 
+  // Also compute relative position in the annotations.
+  if (psd->mFrame->mFrame->GetType() == nsGkAtoms::rubyFrame) {
+    RelativePositionAnnotations(psd, overflowAreas);
+  }
+
   // If we just computed a spans combined area, we need to update its
   // overflow rect...
   if (psd != mRootSpan) {
     PerFrameData* spanPFD = psd->mFrame;
     nsIFrame* frame = spanPFD->mFrame;
     frame->FinishAndStoreOverflow(overflowAreas, frame->GetSize());
   }
   aOverflowAreas = overflowAreas;

--- a/layout/generic/nsLineLayout.h
+++ b/layout/generic/nsLineLayout.h
@@ -662,16 +662,19 @@ protected:
   void VerticalAlignFrames(PerSpanData* psd);
 
   void PlaceTopBottomFrames(PerSpanData* psd,
                             nscoord aDistanceFromStart,
                             nscoord aLineBSize);
 
   void ApplyRelativePositioning(PerFrameData* aPFD);
 
+  void RelativePositionAnnotations(PerSpanData* aRubyPSD,
+                                   nsOverflowAreas& aOverflowAreas);
+
   void RelativePositionFrames(PerSpanData* psd, nsOverflowAreas& aOverflowAreas);
 
   bool TrimTrailingWhiteSpaceIn(PerSpanData* psd, nscoord* aDeltaISize);
 
   struct JustificationComputationState;
   int32_t ComputeFrameJustification(PerSpanData* psd,
                                     JustificationComputationState& aState);