Convert MouseEvents from DIPS to Pixels before passing it to surfaces for hittesting.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index 2666b127ad2653a32978b6a40e4b7aa4e8646a0e..3c5c4e49be2697cd08106a7f4c616e5830aaa4a9 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -2167,8 +2167,13 @@ void RenderWidgetHostViewAura::OnMouseEvent(ui::MouseEvent* event) {
 uint32_t RenderWidgetHostViewAura::SurfaceIdNamespaceAtPoint(
     const gfx::Point& point,
     gfx::Point* transformed_point) {
-  cc::SurfaceId id =
-      delegated_frame_host_->SurfaceIdAtPoint(point, transformed_point);
+  aura::WindowTreeHost* host = window_->GetHost();
+  gfx::Point point_in_pixels(point);
+  host->GetRootTransform().TransformPoint(&point_in_pixels);

[sadrul, 2015/09/11 17:48:10]

Does this do the right thing when the display is rotated on a chromeos device?
Because the root-transform possibly includes the rotation transforms that you
don't want to use?

Also, can you add tests?

+  cc::SurfaceId id = delegated_frame_host_->SurfaceIdAtPoint(point_in_pixels,
+                                                             transformed_point);
+  host->GetInverseRootTransform().TransformPoint(transformed_point);
+
   // It is possible that the renderer has not yet produced a surface, in which
   // case we return our current namespace.
   if (id.is_null())