mash: Move ownership of ShelfDelegate to WmShell

ash/metrics/user_metrics_recorder.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/metrics/user_metrics_recorder.h"
 
 #include "ash/common/session/session_state_delegate.h"
+#include "ash/common/shelf/shelf_delegate.h"
 #include "ash/common/shelf/shelf_item_types.h"
 #include "ash/common/shelf/shelf_model.h"
 #include "ash/common/shell_window_ids.h"
 #include "ash/common/system/tray/system_tray_delegate.h"
 #include "ash/common/wm/window_state.h"
 #include "ash/common/wm_shell.h"
 #include "ash/metrics/desktop_task_switch_metric_recorder.h"
 #include "ash/shelf/shelf.h"
-#include "ash/shelf/shelf_delegate.h"
 #include "ash/shelf/shelf_view.h"
 #include "ash/shell.h"
 #include "ash/wm/window_state_aura.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/user_metrics.h"
 #include "ui/aura/window.h"
 
 namespace ash {
 
 namespace {
@@ skipping 123 matching lines @@
         maximized_or_fullscreen_window_present = true;
         break;
       }
     }
   }
   return visible_window_count;
 }
 
 // Records the number of items in the shelf as an UMA statistic.
 void RecordShelfItemCounts() {
-  ShelfDelegate* shelf_delegate = Shell::GetInstance()->GetShelfDelegate();
+  ShelfDelegate* shelf_delegate = WmShell::Get()->shelf_delegate();

[msw, 2016/07/23 00:02:36]

Couldn't this now be null if no shelves have called CreateShelfDelegate? The old
accessor would lazily create the shelf delegate if needed. ditto elsewhere

[James Cook, 2016/07/23 00:38:03]

Added DCHECKs.

I thought the lazy construction before was confusing. I could not tell by
reading the code when the object was created. If you think it's better to lazily
create the delegate then I'm happy to move it into the getter.

   int pinned_item_count = 0;
   int unpinned_item_count = 0;
 
   for (const ShelfItem& shelf_item : WmShell::Get()->shelf_model()->items()) {
     if (shelf_item.type != TYPE_APP_LIST) {
       // Internal ash apps do not have an app id and thus will always be counted
       // as unpinned.
       if (shelf_delegate->HasShelfIDToAppIDMapping(shelf_item.id) &&
           shelf_delegate->IsAppPinned(
               shelf_delegate->GetAppIDForShelfID(shelf_item.id))) {
@@ skipping 453 matching lines @@
   return IsUserActive() && !IsKioskModeActive();
 }
 
 void UserMetricsRecorder::StartTimer() {
   timer_.Start(FROM_HERE,
                base::TimeDelta::FromSeconds(kAshPeriodicMetricsTimeInSeconds),
                this, &UserMetricsRecorder::RecordPeriodicMetrics);
 }
 
 }  // namespace ash