IWYU: include <memory> in bubble_menu_item_factory.h as it uses std::unique_ptr

GCC build fixes because of missing include of <memory>:
../../chrome/browser/ui/views/bubble_menu_item_factory.h:20:6: error: ‘unique_ptr’ in namespace ‘std’ does not name a template type
 std::unique_ptr<views::LabelButton> CreateBubbleMenuItem(

Bug: 819294
Change-Id: I1c48566175e313e964e4a474daa444eb4fccf3bf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1879229
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709404}

chrome/browser/ui/views/bubble_menu_item_factory.h

@@ -5,6 +5,7 @@
 #ifndef CHROME_BROWSER_UI_VIEWS_BUBBLE_MENU_ITEM_FACTORY_H_
 #define CHROME_BROWSER_UI_VIEWS_BUBBLE_MENU_ITEM_FACTORY_H_
 
+#include <memory>
 #include <string>
 
 #include "base/strings/string16.h"