Add a second kind of HandleScope that ties the lifetime of Handles created in its scope to the life…

src/handles.h

Index: src/handles.h
diff --git a/src/handles.h b/src/handles.h
index 960696b5fb81f705f2128b5586fef44ca0c8e7fb..4851c6ac1b72e418167b9667a8c292fcd34ded44 100644
--- a/src/handles.h
+++ b/src/handles.h
@@ -161,6 +161,25 @@ class HandleScope {
 };
 
 
+class CompilationInfo;
+
+// Like a regular stack-allocated HandleScope, but does not delete the
+// handles allocated in its scope on destruction.  Instead, it ties
+// the Handles created in its scope with the CompilatationInfo passed
+// to its constructor.  The Handles are reclaimed when the
+// CompilationInfo destructs.
+class GatheringHandleScope {
+ public:
+  explicit GatheringHandleScope(CompilationInfo* info);
+  ~GatheringHandleScope();
+
+ private:
+  CompilationInfo* info_;
+  Object** prev_next_;
+  Object** prev_limit_;
+};
+
+
 // ----------------------------------------------------------------------------
 // Handle operations.
 // They might invoke garbage collection. The result is an handle to