MacViews: Fix GetOffsetFromRootSurface

This should be based off of the ui::Layer heirarchy, not the NSView
heirarchy.

Bug: 860344
Change-Id: I307a1d681a21846886bb6118a3e3acf97c2b268e
Reviewed-on: https://chromium-review.googlesource.com/1144215
Commit-Queue: ccameron <ccameron@chromium.org>
Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577073}

content/browser/renderer_host/browser_compositor_view_mac.h

@@ -121,6 +121,7 @@ class CONTENT_EXPORT BrowserCompositorMac : public DelegatedFrameHostClient,
   const viz::LocalSurfaceId& AllocateNewRendererLocalSurfaceId();
   bool UpdateRendererLocalSurfaceIdFromChild(
       const viz::LocalSurfaceId& child_allocated_local_surface_id);
+  void TransformPointToRootSurface(gfx::PointF* point);
 
   // Indicate that the recyclable compositor should be destroyed, and no future
   // compositors should be recycled.

content/browser/renderer_host/browser_compositor_view_mac.mm

@@ -472,6 +472,14 @@ bool BrowserCompositorMac::UpdateRendererLocalSurfaceIdFromChild(
       child_allocated_local_surface_id);
 }
 
+void BrowserCompositorMac::TransformPointToRootSurface(gfx::PointF* point) {
+  gfx::Transform transform_to_root;
+  if (parent_ui_layer_)
+    parent_ui_layer_->GetTargetTransformRelativeTo(nullptr, &transform_to_root);
+  gfx::Point origin_in_root;
+  transform_to_root.TransformPoint(&origin_in_root);
+}
+
 void BrowserCompositorMac::LayerDestroyed(ui::Layer* layer) {
   DCHECK_EQ(layer, parent_ui_layer_);
   SetParentUiLayer(nullptr);

content/browser/renderer_host/render_widget_host_view_mac.mm

@@ -1043,8 +1043,7 @@ bool RenderWidgetHostViewMac::RequestRepaintForTesting() {
 }
 
 void RenderWidgetHostViewMac::TransformPointToRootSurface(gfx::PointF* point) {
-  if (display_only_using_parent_ui_layer_)
-    *point += view_bounds_in_window_dip_.OffsetFromOrigin();
+  browser_compositor_->TransformPointToRootSurface(point);
 }
 
 gfx::Rect RenderWidgetHostViewMac::GetBoundsInRootWindow() {