Implement a Hit Test Cache.

Source/core/layout/line/InlineFlowBox.cpp

 /*
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 957 matching lines @@
 
     LayoutRect visualOverflow(isHorizontal() ? logicalVisualOverflow : logicalVisualOverflow.transposedRect());
     setVisualOverflow(visualOverflow, frameBox);
 }
 
 bool InlineFlowBox::nodeAtPoint(HitTestResult& result, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, LayoutUnit lineTop, LayoutUnit lineBottom)
 {
     LayoutRect overflowRect(visualOverflowRect(lineTop, lineBottom));
     flipForWritingMode(overflowRect);
     overflowRect.moveBy(accumulatedOffset);
-    if (!locationInContainer.intersects(overflowRect))
+    if (!locationInContainer.intersects(overflowRect)) {
+        result.shrinkValidityRect(overflowRect);
         return false;
+    }
 
     // We need to hit test both our inline children (InlineBoxes) and culled inlines
     // (LayoutObjects). We check our inlines in the same order as line layout but
     // for each inline we additionally need to hit test its culled inline parents.
     // While hit testing culled inline parents, we can stop once we reach
     // a non-inline parent or a culled inline associated with a different inline box.
     InlineBox* prev;
     for (InlineBox* curr = lastChild(); curr; curr = prev) {
         prev = curr->prevOnLine();
 
         // Layers will handle hit testing themselves.
         if (curr->boxModelObject() && curr->boxModelObject()->hasSelfPaintingLayer())
             continue;
 
         if (curr->nodeAtPoint(result, locationInContainer, accumulatedOffset, lineTop, lineBottom)) {
-            layoutObject().updateHitTestResult(result, locationInContainer.point() - toLayoutSize(accumulatedOffset));
+            // TODO(dtapuska): Calculate pos based on lineTop/lineBottom
+            layoutObject().updateHitTestResult(result, locationInContainer.point() - toLayoutSize(accumulatedOffset), result.validityRect());
             return true;
         }
 
         // If the current inlinebox's layout object and the previous inlinebox's layout object are same,
         // we should yield the hit-test to the previous inlinebox.
         if (prev && curr->layoutObject() == prev->layoutObject())
             continue;
 
         LayoutObject* culledParent = &curr->layoutObject();
         while (true) {
             LayoutObject* sibling = culledParent->style()->isLeftToRightDirection() ? culledParent->previousSibling() : culledParent->nextSibling();
             culledParent = culledParent->parent();
             ASSERT(culledParent);
 
             if (culledParent == layoutObject() || (sibling && prev && prev->layoutObject().isDescendantOf(culledParent)))
                 break;
 
             if (culledParent->isLayoutInline() && toLayoutInline(culledParent)->hitTestCulledInline(result, locationInContainer, accumulatedOffset))
                 return true;
         }
     }
 
     if (layoutObject().style()->hasBorderRadius()) {
         LayoutRect borderRect = logicalFrameRect();
         borderRect.moveBy(accumulatedOffset);
         FloatRoundedRect border = layoutObject().style()->getRoundedBorderFor(borderRect, includeLogicalLeftEdge(), includeLogicalRightEdge());
-        if (!locationInContainer.intersects(border))
+        if (!locationInContainer.intersects(border)) {
+            result.shrinkValidityRect(borderRect);
             return false;
+        }
     }
 
     // Now check ourselves. Pixel snap hit testing.
     LayoutRect frameRect(roundedFrameRect());
     LayoutUnit minX = frameRect.x();
     LayoutUnit minY = frameRect.y();
     LayoutUnit width = frameRect.width();
     LayoutUnit height = frameRect.height();
 
     // Constrain our hit testing to the line top and bottom if necessary.
     bool noQuirksMode = layoutObject().document().inNoQuirksMode();
     if (!noQuirksMode && !hasTextChildren() && !(descendantsHaveSameLineHeightAndBaseline() && hasTextDescendants())) {
         RootInlineBox& rootBox = root();
         LayoutUnit& top = isHorizontal() ? minY : minX;
         LayoutUnit& logicalHeight = isHorizontal() ? height : width;
         LayoutUnit bottom = std::min(rootBox.lineBottom(), top + logicalHeight);
         top = std::max(rootBox.lineTop(), top);
         logicalHeight = bottom - top;
     }
 
     // Move x/y to our coordinates.
     LayoutRect rect(minX, minY, width, height);
     flipForWritingMode(rect);
     rect.moveBy(accumulatedOffset);
 
     if (visibleToHitTestRequest(result.hitTestRequest()) && locationInContainer.intersects(rect)) {
-        layoutObject().updateHitTestResult(result, flipForWritingMode(locationInContainer.point() - toLayoutSize(accumulatedOffset))); // Don't add in m_x or m_y here, we want coords in the containing block's space.
+        layoutObject().updateHitTestResult(result, flipForWritingMode(locationInContainer.point() - toLayoutSize(accumulatedOffset)), rect); // Don't add in m_x or m_y here, we want coords in the containing block's space.
         if (!result.addNodeToListBasedTestResult(layoutObject().node(), locationInContainer, rect))
             return true;
     }
+    result.shrinkValidityRect(rect);
 
     return false;
 }
 
 void InlineFlowBox::paint(const PaintInfo& paintInfo, const LayoutPoint& paintOffset, LayoutUnit lineTop, LayoutUnit lineBottom)
 {
     InlineFlowBoxPainter(*this).paint(paintInfo, paintOffset, lineTop, lineBottom);
 }
 
 bool InlineFlowBox::boxShadowCanBeAppliedToBackground(const FillLayer& lastBackgroundLayer) const
@@ skipping 246 matching lines @@
         ASSERT(child->prevOnLine() == prev);
         prev = child;
     }
     ASSERT(prev == m_lastChild);
 #endif
 }
 
 #endif
 
 } // namespace blink