Copy contents of ui/base/ios into ios/chrome/browser/ui/context_menu

ios/web/web_state/ui/crw_context_menu_provider.h

Index: ios/web/web_state/ui/crw_context_menu_provider.h
diff --git a/ios/web/web_state/ui/crw_context_menu_provider.h b/ios/web/web_state/ui/crw_context_menu_provider.h
index cf3b80f2a91c6b5daf4059f0130f8af8723acb9d..6944ebb90e46217080b49c6506a8515fa4c721e1 100644
--- a/ios/web/web_state/ui/crw_context_menu_provider.h
+++ b/ios/web/web_state/ui/crw_context_menu_provider.h
@@ -7,11 +7,14 @@
 #import <Foundation/Foundation.h>
 
 @class CRUContextMenuHolder;
+@class ContextMenuHolder;
 
 // A protocol implemented by a provider of labels and actions for a context
 // menu.
 @protocol CRWContextMenuProvider<NSObject>
 
+// Temporarily optional to allow move of ContextMenuHolder.
+@optional
 // Returns a CRUContextMenuHolder with the titles and actions associated with
 // each menu item. The "Cancel" item is automatically added when constructing
 // the menu for presentation, therefore it should not be added to the list.
@@ -20,6 +23,7 @@
 // |kContextImageURLString| might both be set whereas on a recently visited
 // entry some other identifier will be passed on.
 - (CRUContextMenuHolder*)contextMenuForDictionary:(NSDictionary*)context;
+- (ContextMenuHolder*)contextMenuHolderForDictionary:(NSDictionary*)context;
 
 @end