Add deprecation warning banner to App Launcher on Mac.

ui/app_list/app_list_view_delegate.h

 // Copyright (c) 2012 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.
 
 #ifndef UI_APP_LIST_APP_LIST_VIEW_DELEGATE_H_
 #define UI_APP_LIST_APP_LIST_VIEW_DELEGATE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 147 matching lines @@
 
   // Returns the list of users (for AppListMenu).
   virtual const Users& GetUsers() const = 0;
 
   // Returns true if the app list should be centered and in landscape mode.
   virtual bool ShouldCenterWindow() const = 0;
 
   // Adds/removes an observer for profile changes.
   virtual void AddObserver(AppListViewDelegateObserver* observer) {}
   virtual void RemoveObserver(AppListViewDelegateObserver* observer) {}
+
+#if !defined(OS_CHROMEOS)
+  // Methods to retrieve properties of the message displayed on the app launcher
+  // above the apps grid.
+  virtual base::string16 GetMessageTitle() const;

[Matt Giuca, 2016/03/22 03:56:15]

Also I think these should be =0 and add overrides in AppListTestViewDelegate.
(thoughts?)

[tapted, 2016/03/22 04:19:50]

There's precedent for impure virtuals already for the observers above. I don't
think there's any upside to making these pure - just makes the CL bigger and the
#ifdefs more confusing.

[Matt Giuca, 2016/03/22 04:23:43]

That isn't precedent in my mind -- observers should always be impure. Do these
methods make sense if they are not implemented? If not, they should be pure.

Not that it matters; this code will be short lived. Happy to leave it as-is.

+  virtual base::string16 GetMessageText() const;

[Matt Giuca, 2016/03/22 03:28:06]

// Returns the message text (with the placeholder symbol removed). |offset| is
set to the index where the placeholder was in the string.
virtual base::string16 GetMessageText(size_t* offset) const;

See my comment in app_list_view_controller.mm.

[tapted, 2016/03/22 04:58:14]

Acknowledged.

+  virtual base::string16 GetAppsShortcutName() const;
+  virtual base::string16 GetLearnMoreText() const;
+  virtual base::string16 GetLearnMoreLink() const;
+  virtual gfx::ImageSkia* GetAppsIcon() const;
+  virtual void OpenLearnMoreLink();
+#endif
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_APP_LIST_VIEW_DELEGATE_H_