Debugger: use weak cells to implement ScriptCache.

src/debug.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_DEBUG_H_
 #define V8_DEBUG_H_
 
 #include "src/allocation.h"
 #include "src/arguments.h"
 #include "src/assembler.h"
@@ skipping 210 matching lines @@
   intptr_t original_data_;
   int position_;
   int statement_position_;
 };
 
 
 // Cache of all script objects in the heap. When a script is added a weak handle
 // to it is created and that weak handle is stored in the cache. The weak handle
 // callback takes care of removing the script from the cache. The key used in
 // the cache is the script id.
-class ScriptCache : private HashMap {
+class ScriptCache {
  public:
   explicit ScriptCache(Isolate* isolate);
-  virtual ~ScriptCache() { Clear(); }
+  ~ScriptCache();
 
   // Add script to the cache.
   void Add(Handle<Script> script);
 
   // Return the scripts in the cache.
-  Handle<FixedArray> GetScripts();
+  Handle<FixedArray> GetScripts() {
+    return WeakValueHashTable::GetWeakValues(table_);
+  }
 
  private:
-  // Calculate the hash value from the key (script id).
-  static uint32_t Hash(int key) {
-    return ComputeIntegerHash(key, v8::internal::kZeroHashSeed);
-  }
-
-  // Clear the cache releasing all the weak handles.
-  void Clear();
-
-  // Weak handle callback for scripts in the cache.
-  static void HandleWeakScript(
-      const v8::WeakCallbackData<v8::Value, void>& data);
-
   Isolate* isolate_;
+  Handle<WeakValueHashTable> table_;
 };
 
 
 // Linked list holding debug info objects. The debug info objects are kept as
 // weak handles to avoid a debug info object to keep a function alive.
 class DebugInfoListNode {
  public:
   explicit DebugInfoListNode(DebugInfo* debug_info);
   virtual ~DebugInfoListNode() { ClearInfo(); }
 
@@ skipping 573 matching lines @@
   // several frames above.
   // There is no calling conventions here, because it never actually gets
   // called, it only gets returned to.
   static void GenerateFrameDropperLiveEdit(MacroAssembler* masm);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_DEBUG_H_