NativeAppWindowGtk: only notify change when the window state actually changes

chrome/browser/ui/gtk/apps/native_app_window_gtk.cc

 // Copyright 2013 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 "chrome/browser/ui/gtk/apps/native_app_window_gtk.h"
 
 #include <gdk/gdkx.h>
 #include <vector>
 
 #include "base/message_loop/message_pump_gtk.h"
@@ skipping 312 matching lines @@
       x_event->xproperty.atom == atom_cache_.GetAtom("_NET_WM_STATE") &&
       GTK_WIDGET(window_)->window &&
       ui::GetAtomArrayProperty(GDK_WINDOW_XWINDOW(GTK_WIDGET(window_)->window),
                                "_NET_WM_STATE",
                                &atom_list)) {
     std::vector< ::Atom>::iterator it =
         std::find(atom_list.begin(),
                   atom_list.end(),
                   atom_cache_.GetAtom("_NET_WM_STATE_HIDDEN"));
 
+    GdkWindowState previous_state = state_;
     state_ = (it != atom_list.end()) ? GDK_WINDOW_STATE_ICONIFIED :
         static_cast<GdkWindowState>(state_ & ~GDK_WINDOW_STATE_ICONIFIED);
 
-    // TODO(mlamouri): we don't need to send a change event all the time here.
-    // Only when |state_| has actually changed.
-    shell_window_->OnNativeWindowChanged();
+    if (previous_state != state_) {
+      shell_window_->OnNativeWindowChanged();
+    }
   }
 
   return GDK_FILTER_CONTINUE;
 }
 
 void NativeAppWindowGtk::FlashFrame(bool flash) {
   gtk_window_set_urgency_hint(window_, flash);
 }
 
 bool NativeAppWindowGtk::IsAlwaysOnTop() const {
@@ skipping 361 matching lines @@
     hints_mask |= GDK_HINT_MAX_SIZE;
   }
   if (hints_mask) {
     gtk_window_set_geometry_hints(
         window_,
         GTK_WIDGET(window_),
         &hints,
         static_cast<GdkWindowHints>(hints_mask));
   }
 }