exo: Only create new SurfaceLayer if layer properties change.

components/exo/shell_surface.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/exo/shell_surface.h"
 
 #include "ash/aura/wm_window_aura.h"
 #include "ash/common/shell_window_ids.h"
 #include "ash/common/wm/window_resizer.h"
 #include "ash/common/wm/window_state.h"
@@ skipping 379 matching lines @@
       new base::trace_event::TracedValue());
   value->SetString("title", base::UTF16ToUTF8(title_));
   value->SetString("application_id", application_id_);
   return value;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // SurfaceDelegate overrides:
 
 void ShellSurface::OnSurfaceCommit() {
+  surface_->CheckForCommittingToNewSurface();
   surface_->CommitSurfaceHierarchy();
 
   if (enabled() && !widget_)
     CreateShellSurfaceWidget(ui::SHOW_STATE_NORMAL);
 
   // Apply the accumulated pending origin offset to reflect acknowledged
   // configure requests.
   origin_ += pending_origin_offset_;
   pending_origin_offset_ = gfx::Vector2d();
 
@@ skipping 553 matching lines @@
   DCHECK(!ignore_window_bounds_changes_);
   ignore_window_bounds_changes_ = true;
   widget_->SetBounds(new_widget_bounds);
   ignore_window_bounds_changes_ = false;
 
   // A change to the widget size requires surface bounds to be re-adjusted.
   surface_->SetBounds(gfx::Rect(GetSurfaceOrigin(), surface_->layer()->size()));
 }
 
 }  // namespace exo