[gin] Make a new IsolateHolder ctor for snapshot

gin/public/isolate_holder.h

 // Copyright 2013 The Chromium 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 GIN_PUBLIC_ISOLATE_HOLDER_H_
 #define GIN_PUBLIC_ISOLATE_HOLDER_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 42 matching lines @@
     kStableAndExperimentalV8Extras,
   };
 
   explicit IsolateHolder(
       scoped_refptr<base::SingleThreadTaskRunner> task_runner);
   IsolateHolder(scoped_refptr<base::SingleThreadTaskRunner> task_runner,
                 AccessMode access_mode);
   IsolateHolder(scoped_refptr<base::SingleThreadTaskRunner> task_runner,
                 AccessMode access_mode,
                 AllowAtomicsWaitMode atomics_wait_mode);
+
+  // This constructor is to create V8 snapshot for Blink.
+  // Note this constructor calls isolate->Enter() internally.
+  IsolateHolder(intptr_t* reference_table, v8::StartupData* existing_blob);
+
   ~IsolateHolder();
 
   // Should be invoked once before creating IsolateHolder instances to
   // initialize V8 and Gin. In case V8_USE_EXTERNAL_STARTUP_DATA is
   // defined, V8's initial natives should be loaded (by calling
   // V8Initializer::LoadV8NativesFromFD or
   // V8Initializer::LoadV8Natives) before calling this method.  If the
   // snapshot file is available, it should also be loaded (by calling
   // V8Initializer::LoadV8SnapshotFromFD or
   // V8Initializer::LoadV8Snapshot) before calling this method.
@@ skipping 11 matching lines @@
   // MessageLoop's thread.
   void AddRunMicrotasksObserver();
 
   // This method should also only be called once, and on the MessageLoop's
   // thread.
   void RemoveRunMicrotasksObserver();
 
   // This method returns if v8::Locker is needed to access isolate.
   AccessMode access_mode() const { return access_mode_; }
 
+  v8::SnapshotCreator* snapshot_creator() const {
+    return snapshot_creator_.get();
+  }
+
   void EnableIdleTasks(std::unique_ptr<V8IdleTaskRunner> idle_task_runner);
 
   // This method returns V8IsolateMemoryDumpProvider of this isolate, used for
   // testing.
   V8IsolateMemoryDumpProvider* isolate_memory_dump_provider_for_testing()
       const {
     return isolate_memory_dump_provider_.get();
   }
 
  private:
   v8::Isolate* isolate_;
   std::unique_ptr<PerIsolateData> isolate_data_;
   std::unique_ptr<RunMicrotasksObserver> task_observer_;
   std::unique_ptr<V8IsolateMemoryDumpProvider> isolate_memory_dump_provider_;
+  std::unique_ptr<v8::SnapshotCreator> snapshot_creator_;
   AccessMode access_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(IsolateHolder);
 };
 
 }  // namespace gin
 
 #endif  // GIN_PUBLIC_ISOLATE_HOLDER_H_