Move class hierarchy analysis to its own source.

runtime/vm/cha.h

Index: runtime/vm/cha.h
===================================================================
--- runtime/vm/cha.h	(revision 0)
+++ runtime/vm/cha.h	(revision 0)
@@ -0,0 +1,40 @@
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef VM_CHA_H_
+#define VM_CHA_H_
+
+#include "vm/allocation.h"
+
+namespace dart {
+
+class Function;
+template <typename T> class ZoneGrowableArray;
+class String;
+
+class CHA : public AllStatic {
+ public:
+  // Returns true if the class given by its cid has subclasses.
+  static bool HasSubclasses(intptr_t cid);
+
+  // Returns an array containing the cids of the direct and indirect subclasses
+  // of the class given by its cid.
+  // Must not be called for kDartObjectCid.
+  static ZoneGrowableArray<intptr_t>* GetSubclassIdsOf(intptr_t cid);
+
+  // Returns an array containing instance functions of the given name and
+  // belonging to the classes given by their cids.
+  // Cids must not contain kDartObjectCid.
+  static ZoneGrowableArray<Function*>* GetNamedInstanceFunctionsOf(
+      const ZoneGrowableArray<intptr_t>& cids,
+      const String& function_name);
+
+  // Returns an array of functions overriding the given function.
+  // Must not be called for a function of class Object.
+  static ZoneGrowableArray<Function*>* GetOverridesOf(const Function& function);
+};
+
+}  // namespace dart
+
+#endif  // VM_CHA_H_