chromeos: Add operations to monitor the screen orientation.

chrome/browser/ui/touch/frame/touch_browser_frame_view.cc

Index: chrome/browser/ui/touch/frame/touch_browser_frame_view.cc
diff --git a/chrome/browser/ui/touch/frame/touch_browser_frame_view.cc b/chrome/browser/ui/touch/frame/touch_browser_frame_view.cc
index f5fd86c596c3dbc353920e41453e806f908bb268..4c0dac5c9f36fceb288b8bd0a15be827ede000af 100644
--- a/chrome/browser/ui/touch/frame/touch_browser_frame_view.cc
+++ b/chrome/browser/ui/touch/frame/touch_browser_frame_view.cc
@@ -108,9 +108,10 @@ void TouchBrowserFrameView::OnScreenOrientationChanged(
       initialized_screen_rotation_ = true;
   }
 
-  ui::Transform xform = SideToTransform(change.upward,
-                                        to_rotate->GetTransform(),
-                                        to_rotate->size());
-  to_rotate->SetTransform(xform);
+  const ui::Transform& old_xform = to_rotate->GetTransform();
+  const ui::Transform& new_xform = SideToTransform(change.upward,
+                                                   old_xform,
+                                                   to_rotate->size());
+  if (old_xform != new_xform)
+    to_rotate->SetTransform(new_xform);
 }
-