Introduce phantom weak handles in the API and use them internally for debug info

src/compiler.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/compiler.h"
 
 #include "src/ast-numbering.h"
 #include "src/bootstrapper.h"
@@ skipping 1290 matching lines @@
   // aggressive about lazy compilation, because it might trigger compilation
   // of functions without an outer context when setting a breakpoint through
   // Debug::FindSharedFunctionInfoInScript.
   bool allow_lazy_without_ctx = literal->AllowsLazyCompilationWithoutContext();
   bool allow_lazy = literal->AllowsLazyCompilation() &&
       !DebuggerWantsEagerCompilation(&info, allow_lazy_without_ctx);
 
 
   if (outer_info->is_toplevel() && outer_info->will_serialize()) {
     // Make sure that if the toplevel code (possibly to be serialized),
-    // the inner unction must be allowed to be compiled lazily.
+    // the inner function must be allowed to be compiled lazily.
     DCHECK(allow_lazy);
   }
 
   // Generate code
   Handle<ScopeInfo> scope_info;
   if (FLAG_lazy && allow_lazy && !literal->is_parenthesized()) {
     Handle<Code> code = isolate->builtins()->CompileLazy();
     info.SetCode(code);
     scope_info = Handle<ScopeInfo>(ScopeInfo::Empty(isolate));
   } else if (Renumber(&info) && FullCodeGenerator::MakeCode(&info)) {
@@ skipping 151 matching lines @@
   AllowHandleDereference allow_deref;
   bool tracing_on = info()->IsStub()
       ? FLAG_trace_hydrogen_stubs
       : (FLAG_trace_hydrogen &&
          info()->closure()->PassesFilter(FLAG_trace_hydrogen_filter));
   return (tracing_on &&
       base::OS::StrChr(const_cast<char*>(FLAG_trace_phase), name_[0]) != NULL);
 }
 
 } }  // namespace v8::internal