Cache experimental natives sources as external strings.

src/debug.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/api.h"
 #include "src/arguments.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
@@ skipping 618 matching lines @@
 
 bool Debug::CompileDebuggerScript(Isolate* isolate, int index) {
   Factory* factory = isolate->factory();
   HandleScope scope(isolate);
 
   // Bail out if the index is invalid.
   if (index == -1) return false;
 
   // Find source and name for the requested script.
   Handle<String> source_code =
-      isolate->bootstrapper()->NativesSourceLookup(index);
+      isolate->bootstrapper()->SourceLookup<Natives>(index);
   Vector<const char> name = Natives::GetScriptName(index);
   Handle<String> script_name =
       factory->NewStringFromAscii(name).ToHandleChecked();
   Handle<Context> context = isolate->native_context();
 
   // Compile the script.
   Handle<SharedFunctionInfo> function_info;
   function_info = Compiler::CompileScript(
       source_code, script_name, 0, 0, false, false, Handle<Object>(), context,
       NULL, NULL, ScriptCompiler::kNoCompileOptions, NATIVES_CODE, false);
@@ skipping 2749 matching lines @@
   logger_->DebugEvent("Put", message.text());
 }
 
 
 void LockingCommandMessageQueue::Clear() {
   base::LockGuard<base::Mutex> lock_guard(&mutex_);
   queue_.Clear();
 }
 
 } }  // namespace v8::internal