Move ownership of the AppListViewDelegate into the AppListService

ash/shell_delegate.h

Index: ash/shell_delegate.h
diff --git a/ash/shell_delegate.h b/ash/shell_delegate.h
index d41132b5f78e15aea6a50dccd126f28fce9a8102..148f6867ca331a981be886ccc024a4bbb85e5ff4 100644
--- a/ash/shell_delegate.h
+++ b/ash/shell_delegate.h
@@ -111,9 +111,9 @@ class ASH_EXPORT ShellDelegate {
   // in chrome.
   virtual content::BrowserContext* GetActiveBrowserContext() = 0;
 
-  // Invoked to create an AppListViewDelegate. Shell takes the ownership of
-  // the created delegate.
-  virtual app_list::AppListViewDelegate* CreateAppListViewDelegate() = 0;
+  // Get the AppListViewDelegate, creating one if it does not yet exist.
+  // Ownership stays with Chrome's AppListService, or the ShellDelegate.
+  virtual app_list::AppListViewDelegate* GetAppListViewDelegate() = 0;
 
   // Creates a new ShelfDelegate. Shell takes ownership of the returned
   // value.