Add more tests for mouse rotation,scale&position after display change

ash/test/mirror_window_test_api.h

Index: ash/test/mirror_window_test_api.h
diff --git a/ash/test/mirror_window_test_api.h b/ash/test/mirror_window_test_api.h
index b6758608c93a14da246f7eaeddf1310cf3e6cc98..1dd73aa1e436538487f9ad3097634bc8c4213ec5 100644
--- a/ash/test/mirror_window_test_api.h
+++ b/ash/test/mirror_window_test_api.h
@@ -30,7 +30,15 @@ class MirrorWindowTestApi {
   const aura::WindowTreeHost* GetHost() const;
 
   int GetCurrentCursorType() const;
+
+  // Returns the position of the hot point within the cursor. This is
+  // unaffected by the cursor location.
   const gfx::Point& GetCursorHotPoint() const;
+
+  // Returns the position of the cursor hot point in root window coordinates.
+  // This should be the same as the native cursor location.
+  gfx::Point GetCursorHotPointLocationInRootWindow() const;
+
   const aura::Window* GetCursorWindow() const;
   gfx::Point GetCursorLocation() const;