Refactor LayoutInline::addOutlineRects to avoid tricky logic to avoid dups

Source/core/layout/LayoutInline.cpp

Index: Source/core/layout/LayoutInline.cpp
diff --git a/Source/core/layout/LayoutInline.cpp b/Source/core/layout/LayoutInline.cpp
index 5abf88d5da1e19e4388cb66c7a8d6f1c6e07bb84..e3044721f6f9e24785264a853c24c927b1262ad4 100644
--- a/Source/core/layout/LayoutInline.cpp
+++ b/Source/core/layout/LayoutInline.cpp
@@ -1378,16 +1378,18 @@ public:
 
 void LayoutInline::addOutlineRects(Vector<LayoutRect>& rects, const LayoutPoint& additionalOffset) const
 {
-    // Add line boxes only if this object is the first object of addOutlineRects().
-    // Otherwise the parent (LayoutBlockFlow or LayoutInline) should have added line box rects
-    // covering those of this object.
-    if (rects.isEmpty()) {

[chrishtr, 2015/08/07 17:08:40]

I don't quite get yet why the new version avoids this duplication problem. Can
you explain in more detail?

[Xianzhu, 2015/08/07 17:18:49]

The duplication problem is about LayoutBlocks with inline children. Previously
the call tree was:
 LayoutBlock::addOutlineRects
 1 add rects for line boxes
 2 LayoutBoxModelObject::addOutlineRectsForNormalChildren
 2.1 LayoutBoxModelObject::addOutlineRectsForDescendant
 2.1.1 LayoutInline::addOutlineRects
At 2.1.1 we checked if the rects is empty.

With this CL, 2.1.1 becomes
LayoutInline::addOutlineRectsForChildrenAndContinuations() which doesn't add
rects for line boxes.

-        AbsoluteLayoutRectsIgnoringEmptyRectsGeneratorContext context(rects, additionalOffset);
-        generateLineBoxRects(context);
-    }
-
+    AbsoluteLayoutRectsIgnoringEmptyRectsGeneratorContext context(rects, additionalOffset);
+    generateLineBoxRects(context);
+    addOutlineRectsForChildrenAndContinuations(rects, additionalOffset);
+}
+void LayoutInline::addOutlineRectsForChildrenAndContinuations(Vector<LayoutRect>& rects, const LayoutPoint& additionalOffset) const
+{
     addOutlineRectsForNormalChildren(rects, additionalOffset);
+    addOutlineRectsForContinuations(rects, additionalOffset);
+}
 
+void LayoutInline::addOutlineRectsForContinuations(Vector<LayoutRect>& rects, const LayoutPoint& additionalOffset) const
+{
     if (LayoutBoxModelObject* continuation = this->continuation()) {
         if (continuation->isInline())
             continuation->addOutlineRects(rects, additionalOffset + (continuation->containingBlock()->location() - containingBlock()->location()));