Remove thin context as it's dead code

src/bootstrapper.h

 // Copyright 2014 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_BOOTSTRAPPER_H_
 #define V8_BOOTSTRAPPER_H_
 
 #include "src/factory.h"
 
 namespace v8 {
@@ skipping 43 matching lines @@
     cache_->set(length + 1, *shared);
     Script::cast(shared->script())->set_type(type_);
   }
 
  private:
   Script::Type type_;
   FixedArray* cache_;
   DISALLOW_COPY_AND_ASSIGN(SourceCodeCache);
 };
 
-enum GlobalContextType { FULL_CONTEXT, THIN_CONTEXT, DEBUG_CONTEXT };
+enum GlobalContextType { FULL_CONTEXT, DEBUG_CONTEXT };
 
 // The Boostrapper is the public interface for creating a JavaScript global
 // context.
 class Bootstrapper final {
  public:
   static void InitializeOncePerProcess();
   static void TearDownExtensions();
 
   // Requires: Heap::SetUp has been called.
   void Initialize(bool create_heap_objects);
@@ skipping 95 matching lines @@
 
  private:
   const char* data_;
   size_t length_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_BOOTSTRAPPER_H_