Introduce new WebApp header style for hosted apps and fizzy apps on ash.

ash/frame/caption_buttons/frame_size_button.cc

 // Copyright 2014 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/frame/caption_buttons/frame_size_button.h"
 
 #include "ash/metrics/user_metrics_recorder.h"
 #include "ash/screen_util.h"
 #include "ash/shell.h"
 #include "ash/touch/touch_uma.h"
@@ skipping 196 matching lines @@
     switch (to_hover->icon()) {
       case CAPTION_BUTTON_ICON_LEFT_SNAPPED:
         snap_type_ = SNAP_LEFT;
         break;
       case CAPTION_BUTTON_ICON_RIGHT_SNAPPED:
         snap_type_ = SNAP_RIGHT;
         break;
       case CAPTION_BUTTON_ICON_MAXIMIZE_RESTORE:
       case CAPTION_BUTTON_ICON_MINIMIZE:
       case CAPTION_BUTTON_ICON_CLOSE:
+      case CAPTION_BUTTON_ICON_BACK:
       case CAPTION_BUTTON_ICON_COUNT:
         NOTREACHED();
         break;
     }
   }
 
   if (snap_type_ == SNAP_LEFT || snap_type_ == SNAP_RIGHT) {
     aura::Window* window = frame_->GetNativeWindow();
     if (!phantom_window_controller_.get()) {
       phantom_window_controller_.reset(new PhantomWindowController(window));
@@ skipping 48 matching lines @@
 void FrameSizeButton::SetButtonsToNormalMode(
     FrameSizeButtonDelegate::Animate animate) {
   in_snap_mode_ = false;
   snap_type_ = SNAP_NONE;
   set_buttons_to_snap_mode_timer_.Stop();
   delegate_->SetButtonsToNormal(animate);
   phantom_window_controller_.reset();
 }
 
 }  // namespace ash