Fix graphics layer backing and offset for composited selection handles.

This CL:

1. Moves the code out of LayoutObject.
2. Forces the GraphicsLayer to be m_graphicsLayer and not
m_scrollingContentsLayer.

TEST=manual testing
BUG=679674

Review-Url: https://codereview.chromium.org/2620383004
Cr-Commit-Position: refs/heads/master@{#443107}

third_party/WebKit/Source/core/editing/RenderedPosition.cpp

@@ -265,6 +265,41 @@ IntRect RenderedPosition::absoluteRect(
                    .enclosingBoundingBox();
 }
 
+// Convert a local point into the coordinate system of backing coordinates.
+// Also returns the backing layer if needed.
+FloatPoint RenderedPosition::localToInvalidationBackingPoint(
+    const LayoutPoint& localPoint,
+    GraphicsLayer** graphicsLayerBacking) const {
+  const LayoutBoxModelObject& paintInvalidationContainer =
+      m_layoutObject->containerForPaintInvalidation();
+  DCHECK(paintInvalidationContainer.layer());
+
+  FloatPoint containerPoint = m_layoutObject->localToAncestorPoint(
+      FloatPoint(localPoint), &paintInvalidationContainer,
+      TraverseDocumentBoundaries);
+
+  // A layoutObject can have no invalidation backing if it is from a detached
+  // frame, or when forced compositing is disabled.
+  if (paintInvalidationContainer.layer()->compositingState() == NotComposited)
+    return containerPoint;
+
+  PaintLayer::mapPointInPaintInvalidationContainerToBacking(
+      paintInvalidationContainer, containerPoint);
+
+  // Must not use the scrolling contents layer, so pass
+  // |paintInvalidationContainer|.
+  if (GraphicsLayer* graphicsLayer =
+          paintInvalidationContainer.layer()->graphicsLayerBacking(
+              &paintInvalidationContainer)) {
+    if (graphicsLayerBacking)
+      *graphicsLayerBacking = graphicsLayer;
+
+    containerPoint.move(-graphicsLayer->offsetFromLayoutObject());
+  }
+
+  return containerPoint;
+}
+
 void RenderedPosition::positionInGraphicsLayerBacking(
     CompositedSelectionBound& bound,
     bool selectionStart) const {
@@ -275,17 +310,16 @@ void RenderedPosition::positionInGraphicsLayerBacking(
     return;
 
   LayoutRect rect = m_layoutObject->localCaretRect(m_inlineBox, m_offset);
-  PaintLayer* layer = nullptr;
   if (m_layoutObject->style()->isHorizontalWritingMode()) {
-    bound.edgeTopInLayer = m_layoutObject->localToInvalidationBackingPoint(
-        rect.minXMinYCorner(), &layer);
-    bound.edgeBottomInLayer = m_layoutObject->localToInvalidationBackingPoint(
-        rect.minXMaxYCorner(), nullptr);
+    bound.edgeTopInLayer =
+        localToInvalidationBackingPoint(rect.minXMinYCorner(), &bound.layer);
+    bound.edgeBottomInLayer =
+        localToInvalidationBackingPoint(rect.minXMaxYCorner(), nullptr);
   } else {
-    bound.edgeTopInLayer = m_layoutObject->localToInvalidationBackingPoint(
-        rect.minXMinYCorner(), &layer);
-    bound.edgeBottomInLayer = m_layoutObject->localToInvalidationBackingPoint(
-        rect.maxXMinYCorner(), nullptr);
+    bound.edgeTopInLayer =
+        localToInvalidationBackingPoint(rect.minXMinYCorner(), &bound.layer);
+    bound.edgeBottomInLayer =
+        localToInvalidationBackingPoint(rect.maxXMinYCorner(), nullptr);
 
     // When text is vertical, it looks better for the start handle baseline to
     // be at the starting edge, to enclose the selection fully between the
@@ -299,8 +333,6 @@ void RenderedPosition::positionInGraphicsLayerBacking(
     // Flipped blocks writing mode is not only vertical but also right to left.
     bound.isTextDirectionRTL = m_layoutObject->hasFlippedBlocksWritingMode();
   }
-
-  bound.layer = layer ? layer->graphicsLayerBacking() : nullptr;
 }
 
 bool layoutObjectContainsPosition(LayoutObject* target,

third_party/WebKit/Source/core/editing/RenderedPosition.h

@@ -38,6 +38,8 @@
 
 namespace blink {
 
+class GraphicsLayer;
+class LayoutPoint;
 class LayoutUnit;
 class LayoutObject;
 struct CompositedSelectionBound;
@@ -102,6 +104,10 @@ class RenderedPosition {
   bool atRightBoundaryOfBidiRun(ShouldMatchBidiLevel,
                                 unsigned char bidiLevelOfRun) const;
 
+  FloatPoint localToInvalidationBackingPoint(
+      const LayoutPoint& localPoint,
+      GraphicsLayer** graphicsLayerBacking) const;
+
   LayoutObject* m_layoutObject;
   InlineBox* m_inlineBox;
   int m_offset;

third_party/WebKit/Source/core/layout/LayoutObject.cpp

@@ -2315,35 +2315,6 @@ TransformationMatrix LayoutObject::localToAncestorTransform(
   return transformState.accumulatedTransform();
 }
 
-FloatPoint LayoutObject::localToInvalidationBackingPoint(
-    const LayoutPoint& localPoint,
-    PaintLayer** backingLayer) {
-  const LayoutBoxModelObject& paintInvalidationContainer =
-      containerForPaintInvalidation();
-  DCHECK(paintInvalidationContainer.layer());
-
-  if (backingLayer)
-    *backingLayer = paintInvalidationContainer.layer();
-  FloatPoint containerPoint =
-      localToAncestorPoint(FloatPoint(localPoint), &paintInvalidationContainer,
-                           TraverseDocumentBoundaries);
-
-  // A layoutObject can have no invalidation backing if it is from a detached
-  // frame, or when forced compositing is disabled.
-  if (paintInvalidationContainer.layer()->compositingState() == NotComposited)
-    return containerPoint;
-
-  PaintLayer::mapPointInPaintInvalidationContainerToBacking(
-      paintInvalidationContainer, containerPoint);
-
-  if (GraphicsLayer* backingLayer =
-          paintInvalidationContainer.layer()->graphicsLayerBacking(this)) {
-    containerPoint.move(-backingLayer->offsetFromLayoutObject());
-  }
-
-  return containerPoint;
-}
-
 LayoutSize LayoutObject::offsetFromContainer(const LayoutObject* o) const {
   ASSERT(o == container());
   return o->hasOverflowClip()

third_party/WebKit/Source/core/layout/LayoutObject.h

@@ -1204,12 +1204,6 @@ class CORE_EXPORT LayoutObject : public ImageResourceObserver,
     return localToAncestorTransform(nullptr, mode);
   }
 
-  // Convert a local point into the coordinate system of backing coordinates.
-  // Also returns the backing layer if needed.
-  FloatPoint localToInvalidationBackingPoint(
-      const LayoutPoint&,
-      PaintLayer** backingLayer = nullptr);
-
   // Return the offset from the container() layoutObject (excluding transforms
   // and multicol).
   virtual LayoutSize offsetFromContainer(const LayoutObject*) const;