Fix a bunch of spelling mistakes :\

src/heap.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 716 matching lines @@
   static inline bool allow_allocation(bool enable);
 
   static bool disallow_allocation_failure() {
     return disallow_allocation_failure_;
   }
 
   static void TracePathToObject();
   static void TracePathToGlobal();
 #endif
 
-  // Callback function pased to Heap::Iterate etc.  Copies an object if
+  // Callback function passed to Heap::Iterate etc.  Copies an object if
   // necessary, the object might be promoted to an old space.  The caller must
   // ensure the precondition that the object is (a) a heap object and (b) in
   // the heap's from space.
   static void ScavengePointer(HeapObject** p);
   static inline void ScavengeObject(HeapObject** p, HeapObject* object);
 
   // Clear a range of remembered set addresses corresponding to the object
   // area address 'start' with size 'size_in_bytes', eg, when adding blocks
   // to the free list.
   static void ClearRSetRange(Address start, int size_in_bytes);
@@ skipping 538 matching lines @@
   int marked_count_;
 
   // The count from the end of the previous full GC.  Will be zero if there
   // was no previous full GC.
   int previous_marked_count_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_