Fix errors in display resolution change notifications

ash/display/resolution_notification_controller_unittest.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 "ash/display/resolution_notification_controller.h"
 
 #include "ash/screen_util.h"
 #include "ash/shell.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "ash/test/ash_test_base.h"
@@ skipping 48 matching lines @@
     scoped_refptr<display::ManagedDisplayMode> old_mode(
         new display::ManagedDisplayMode(
             info.size_in_pixel(), 60 /* refresh_rate */, false /* interlaced */,
             false /* native */));
     scoped_refptr<display::ManagedDisplayMode> new_mode(
         new display::ManagedDisplayMode(
             new_resolution, old_mode->refresh_rate(), old_mode->is_interlaced(),
             old_mode->native(), old_mode->ui_scale(),
             old_mode->device_scale_factor()));
 
-    if (display_manager()->SetDisplayMode(display.id(), new_mode)) {
-      controller()->PrepareNotification(
-          display.id(), old_mode, new_mode,
-          base::Bind(&ResolutionNotificationControllerTest::OnAccepted,
-                     base::Unretained(this)));
-    }
+    EXPECT_TRUE(controller()->PrepareNotificationAndSetDisplayMode(
+        display.id(), old_mode, new_mode,
+        base::Bind(&ResolutionNotificationControllerTest::OnAccepted,
+                   base::Unretained(this))));
 
     // OnConfigurationChanged event won't be emitted in the test environment,
     // so invoke UpdateDisplay() to emit that event explicitly.
     std::vector<display::ManagedDisplayInfo> info_list;
     for (size_t i = 0; i < display_manager()->GetNumDisplays(); ++i) {
       int64_t id = display_manager()->GetDisplayAt(i).id();
       display::ManagedDisplayInfo info = display_manager()->GetDisplayInfo(id);
       if (display.id() == id) {
         gfx::Rect bounds = info.bounds_in_native();
         bounds.set_size(actual_new_resolution);
@@ skipping 293 matching lines @@
   EXPECT_FALSE(IsNotificationVisible());
   EXPECT_EQ(0, accept_count());
 
   mode = display_manager()->GetSelectedModeForDisplayId(id2);
   EXPECT_TRUE(!!mode);
   EXPECT_EQ("250x250", mode->size().ToString());
   EXPECT_EQ(58.0f, mode->refresh_rate());
 }
 
 }  // namespace ash