WeakHashTable::Lookup() handlified and ObjectHashTable's interface cleaned up.

src/heap.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_HEAP_H_
 #define V8_HEAP_H_
 
 #include <cmath>
 
 #include "allocation.h"
@@ skipping 1644 matching lines @@
       heap_->relocation_mutex_.Unlock();
     }
 
    private:
     Heap* heap_;
   };
 
   void AddWeakObjectToCodeDependency(Handle<Object> obj,
                                      Handle<DependentCode> dep);
 
-  DependentCode* LookupWeakObjectToCodeDependency(Object* obj);
+  DependentCode* LookupWeakObjectToCodeDependency(Handle<Object> obj);
 
   void InitializeWeakObjectToCodeTable() {
     set_weak_object_to_code_table(undefined_value());
   }
 
   void EnsureWeakObjectToCodeTable();
 
   static void FatalProcessOutOfMemory(const char* location,
                                       bool take_snapshot = false);
 
@@ skipping 1182 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_