Route selection bounds updates through WebLayerTreeView

Source/core/editing/RenderedPosition.cpp

Index: Source/core/editing/RenderedPosition.cpp
diff --git a/Source/core/editing/RenderedPosition.cpp b/Source/core/editing/RenderedPosition.cpp
index f350387d5fbcf04f916dbf4edf91106410d482d4..2f61555b8f1a5e3782b5fee09ea74c1c4cb1e76e 100644
--- a/Source/core/editing/RenderedPosition.cpp
+++ b/Source/core/editing/RenderedPosition.cpp
@@ -33,6 +33,8 @@
 
 #include "core/dom/Position.h"
 #include "core/editing/VisiblePosition.h"
+#include "core/rendering/RenderLayer.h"
+#include "core/rendering/compositing/CompositedSelectionBound.h"
 
 namespace blink {
 
@@ -231,6 +233,24 @@ IntRect RenderedPosition::absoluteRect(LayoutUnit* extraWidthToEndOfLine) const
     return localRect == IntRect() ? IntRect() : m_renderer->localToAbsoluteQuad(FloatRect(localRect)).enclosingBoundingBox();
 }
 
+void RenderedPosition::positionInGraphicsLayerBacking(CompositedSelectionBound& bound) const
+{
+    bound.layer = nullptr;
+    bound.edgeTopInLayer = bound.edgeBottomInLayer = FloatPoint();
+
+    if (isNull())
+        return;
+
+    LayoutRect rect = m_renderer->localCaretRect(m_inlineBox, m_offset);
+    if (rect == LayoutRect())
+        return;
+
+    RenderLayer* layer;
+    bound.edgeTopInLayer = m_renderer->localToInvalidationBackingPoint(rect.minXMinYCorner(), &layer);
+    bound.edgeBottomInLayer = m_renderer->localToInvalidationBackingPoint(rect.minXMaxYCorner(), nullptr);
+    bound.layer = layer->graphicsLayerBacking();
+}
+
 bool renderObjectContainsPosition(RenderObject* target, const Position& position)
 {
     for (RenderObject* renderer = rendererFromPosition(position); renderer && renderer->node(); renderer = renderer->parent()) {