Refactor the "proxy action" behavior of Command to Utils::ProxyAction

A generic action that acts as a proxy for another (changeable) action,
like it is used for mostly all of the visible actions in Qt Creator
through the action manager.

src/plugins/coreplugin/actionmanager/command.h

@@ -54,12 +54,12 @@ class CORE_EXPORT Command : public QObject
     Q_OBJECT
 public:
     enum CommandAttribute {
-        CA_Hide             = 0x0100,
-        CA_UpdateText       = 0x0200,
-        CA_UpdateIcon       = 0x0400,
-        CA_NonConfigureable = 0x8000,
-        CA_Mask             = 0xFF00
+        CA_Hide,
+        CA_UpdateText,
+        CA_UpdateIcon,
+        CA_NonConfigureable
     };
+    Q_DECLARE_FLAGS(CommandAttributes, CommandAttribute)
 
     virtual void setDefaultKeySequence(const QKeySequence &key) = 0;
     virtual QKeySequence defaultKeySequence() const = 0;
@@ -95,4 +95,6 @@ signals:
 
 } // namespace Core
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(Core::Command::CommandAttributes)
+
 #endif // COMMAND_H