Reduce excessive calls of OnTouchableBoundsChanged().

A bounds in pixel and a bounds in DIP are compared.
It causes InputMethodSurface call OnTouchableBoundsChanged() always.

Bug: 1042549
Change-Id: I1cd0fafd8e754aced022acd2f3f7aa61c6ce7fc5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2043337
Auto-Submit: Yuichiro Hanada <yhanada@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Yuichiro Hanada <yhanada@chromium.org>
Cr-Commit-Position: refs/heads/master@{#740511}

components/exo/input_method_surface.cc

@@ -70,10 +70,10 @@ void InputMethodSurface::OnSurfaceCommit() {
     manager_->AddSurface(this);
   }
 
-  gfx::Rect new_bounds = root_surface()->hit_test_region().bounds();
+  const gfx::Rect new_bounds = gfx::ConvertRectToDIP(
+      default_device_scale_factor_, root_surface()->hit_test_region().bounds());
   if (input_method_bounds_ != new_bounds) {
-    input_method_bounds_ =
-        gfx::ConvertRectToDIP(default_device_scale_factor_, new_bounds);
+    input_method_bounds_ = new_bounds;
     manager_->OnTouchableBoundsChanged(this);
 
     GetViewAccessibility().OverrideBounds(gfx::RectF(input_method_bounds_));