Handle floating point coordinates from ozone to exosphere

ash/display/mirror_window_controller.cc

Index: ash/display/mirror_window_controller.cc
diff --git a/ash/display/mirror_window_controller.cc b/ash/display/mirror_window_controller.cc
index b0e2d24f58708b56af2c74c3faee2a115031379d..0a21c61617f73d08d4a0251fa4f9ed4d9f49ae25 100644
--- a/ash/display/mirror_window_controller.cc
+++ b/ash/display/mirror_window_controller.cc
@@ -56,8 +56,15 @@ class MirroringScreenPositionClient
 
   void ConvertPointToScreen(const aura::Window* window,
                             gfx::Point* point) override {
+    gfx::PointF point_f(*point);
+    ConvertPointToScreenF(window, &point_f);
+    *point = gfx::ToFlooredPoint(point_f);
+  }
+
+  void ConvertPointToScreenF(const aura::Window* window,
+                             gfx::PointF* point) override {
     const aura::Window* root = window->GetRootWindow();
-    aura::Window::ConvertPointToTarget(window, root, point);
+    aura::Window::ConvertPointToTargetF(window, root, point);
     const display::Display& display =
         controller_->GetDisplayForRootWindow(root);
     const gfx::Point display_origin = display.bounds().origin();
@@ -66,12 +73,19 @@ class MirroringScreenPositionClient
 
   void ConvertPointFromScreen(const aura::Window* window,
                               gfx::Point* point) override {
+    gfx::PointF point_f(*point);
+    ConvertPointFromScreenF(window, &point_f);
+    *point = gfx::ToFlooredPoint(point_f);
+  }
+
+  void ConvertPointFromScreenF(const aura::Window* window,
+                               gfx::PointF* point) override {
     const aura::Window* root = window->GetRootWindow();
     const display::Display& display =
         controller_->GetDisplayForRootWindow(root);
     const gfx::Point display_origin = display.bounds().origin();
     point->Offset(-display_origin.x(), -display_origin.y());
-    aura::Window::ConvertPointToTarget(root, window, point);
+    aura::Window::ConvertPointToTargetF(root, window, point);
   }
 
   void ConvertHostPointToScreen(aura::Window* root_window,