Two tweaks to avoid invoking ShelfLayoutManager::LayoutShelf unless we

ui/views/controls/image_view.cc

 // Copyright (c) 2011 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 "ui/views/controls/image_view.h"
 
 #include "base/logging.h"
 #include "base/utf_string_conversions.h"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "ui/base/accessibility/accessible_view_state.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/insets.h"
 
 namespace views {
 
 ImageView::ImageView()
     : image_size_set_(false),
       horiz_alignment_(CENTER),
       vert_alignment_(CENTER) {
 }
 
 ImageView::~ImageView() {
 }
 
 void ImageView::SetImage(const SkBitmap& bm) {
+  gfx::Size pref_size(GetPreferredSize());
   image_ = bm;
-  PreferredSizeChanged();
+  if (pref_size != GetPreferredSize())
+    PreferredSizeChanged();
   SchedulePaint();
 }
 
 void ImageView::SetImage(const SkBitmap* bm) {
   if (bm) {
     SetImage(*bm);
   } else {
     SkBitmap t;
     SetImage(t);
   }
@@ skipping 127 matching lines @@
 
 bool ImageView::GetTooltipText(const gfx::Point& p, string16* tooltip) const {
   if (tooltip_text_.empty())
     return false;
 
   *tooltip = GetTooltipText();
   return true;
 }
 
 }  // namespace views