Merge LayoutInline::mapAbsoluteToLocalPoint() into LayoutObject.

Source/core/layout/LayoutObject.cpp

Index: Source/core/layout/LayoutObject.cpp
diff --git a/Source/core/layout/LayoutObject.cpp b/Source/core/layout/LayoutObject.cpp
index e96113c8527123bac9e23bd9410e148474f9f1a9..29e2b7689cc366ddfa2031a13ea849363118fea1 100644
--- a/Source/core/layout/LayoutObject.cpp
+++ b/Source/core/layout/LayoutObject.cpp
@@ -2040,22 +2040,45 @@ void LayoutObject::mapLocalToContainer(const LayoutBoxModelObject* paintInvalida
     if (paintInvalidationContainer == this)
         return;
 
-    LayoutObject* o = parent();
+    if (paintInvalidationState && paintInvalidationState->canMapToContainer(paintInvalidationContainer)) {
+        LayoutSize offset = paintInvalidationState->paintOffset();
+        if (!isText() && style()->hasInFlowPosition() && hasLayer())

[ojan, 2015/06/19 02:21:09]

Nit: I believe a LayoutText can't have a layer, so can you instead put an
ASSERT(!isText()) inside here?

[mstensho (USE GERRIT), 2015/06/19 09:52:42]

Indeed. I can remove it. I put it there, so that we wouldn't check (the
non-inherited) style()->hasInFlowPosition() on text nodes. But yeah, it's an
unnecessary check here, since we require a layer too, which text may never have.

+            offset += toLayoutBoxModelObject(this)->layer()->offsetForInFlowPosition();
+        transformState.move(offset);
+        return;
+    }
+
+    bool containerSkipped;
+    LayoutObject* o = container(paintInvalidationContainer, &containerSkipped);
     if (!o)
         return;
 
-    // FIXME: this should call offsetFromContainer to share code, but I'm not sure it's ever called.
-    LayoutPoint centerPoint = roundedLayoutPoint(transformState.mappedPoint());
     if (mode & ApplyContainerFlip && o->isBox()) {
-        if (o->style()->isFlippedBlocksWritingMode())
-            transformState.move(toLayoutBox(o)->flipForWritingMode(roundedLayoutPoint(transformState.mappedPoint())) - centerPoint);
+        if (o->style()->isFlippedBlocksWritingMode()) {
+            IntPoint centerPoint = roundedIntPoint(transformState.mappedPoint());
+            transformState.move(toLayoutBox(o)->flipForWritingMode(LayoutPoint(centerPoint)) - centerPoint);
+        }
         mode &= ~ApplyContainerFlip;
     }
 
-    transformState.move(o->columnOffset(roundedLayoutPoint(transformState.mappedPoint())));
+    LayoutSize containerOffset = offsetFromContainer(o, roundedLayoutPoint(transformState.mappedPoint()));
 
-    if (o->hasOverflowClip())
-        transformState.move(-toLayoutBox(o)->scrolledContentOffset());
+    bool preserve3D = mode & UseTransforms && (o->style()->preserves3D() || (!isText() && style()->preserves3D()));

[ojan, 2015/06/19 02:21:09]

I don't think this is right. Even if your parent preserves3D, I don't think the
LayoutText wants to.

[mstensho (USE GERRIT), 2015/06/19 09:52:42]

First of all: this was an unintended change from my side.

So, if a parent preserves3D, a LayoutInline should too, while a LayoutText
shouldn't? I have no idea, but that does sound inconsistent. But OK, to err on
the safe side, I'd better add a broader !isText() check.

+    if (mode & UseTransforms && shouldUseTransformFromContainer(o)) {
+        TransformationMatrix t;
+        getTransformFromContainer(o, containerOffset, t);
+        transformState.applyTransform(t, preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
+    } else {
+        transformState.move(containerOffset.width(), containerOffset.height(), preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
+    }
+
+    if (containerSkipped) {
+        // There can't be a transform between paintInvalidationContainer and o, because transforms create containers, so it should be safe
+        // to just subtract the delta between the paintInvalidationContainer and o.
+        LayoutSize containerOffset = paintInvalidationContainer->offsetFromAncestorContainer(o);
+        transformState.move(-containerOffset.width(), -containerOffset.height(), preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
+        return;
+    }
 
     o->mapLocalToContainer(paintInvalidationContainer, transformState, mode, wasFixed, paintInvalidationState);
 }