Eliminate interface bool

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 11354)
+++ runtime/vm/object.h	(working copy)
@@ -865,8 +865,8 @@
         Class::Handle(type_class()).IsObjectClass();
   }
 
-  // Check if this type represents the 'bool' interface.
-  bool IsBoolInterface() const;
+  // Check if this type represents the 'bool' type.
+  bool IsBoolType() const;
 
   // Check if this type represents the 'int' interface.
   bool IsIntInterface() const;
@@ -983,8 +983,8 @@
   // The 'Object' type.
   static RawType* ObjectType();
 
-  // The 'bool' interface type.
-  static RawType* BoolInterface();
+  // The 'bool' type.
+  static RawType* BoolType();
 
   // The 'int' interface type.
   static RawType* IntInterface();
@@ -3888,6 +3888,7 @@
 };
 
 
+// Class Bool implements Dart core class bool.
 class Bool : public Instance {
  public:
   bool value() const {