[Bindings] Create and use V8 context snapshots

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 35 matching lines @@
     kDisallowAtomicsWait,
     kAllowAtomicsWait
   };
 
   // Indicates whether V8 works with stable or experimental v8 extras.
   enum V8ExtrasMode {
     kStableV8Extras,
     kStableAndExperimentalV8Extras,
   };
 
+  enum V8ContextMode {
+    kDefault,
+    kTakeSnapshot,
+    kUseSnapshot,
+  };
+
   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);
+                AllowAtomicsWaitMode atomics_wait_mode,
+                intptr_t*,

[Yuki, 2017/05/12 15:20:09]

nit: Write the argument name that is not trivial. 
v8_snapshot_external_references?

[peria, 2017/05/30 08:25:41]

Done.

+                V8ContextMode);
   ~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.
   static void Initialize(ScriptMode mode,
                          V8ExtrasMode v8_extras_mode,
                          v8::ArrayBuffer::Allocator* allocator);
 
   v8::Isolate* isolate() { return isolate_; }
+  v8::SnapshotCreator* snapshot_creator() { return snapshot_creator_.get(); }
 
   // The implementations of Object.observe() and Promise enqueue v8 Microtasks
   // that should be executed just before control is returned to the message
   // loop. This method adds a MessageLoop TaskObserver which runs any pending
   // Microtasks each time a Task is completed. This method should be called
   // once, when a MessageLoop is created and it should be called on the
   // 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_; }
 
   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();
   }
 
+  V8ContextMode v8_context_mode() const { return v8_context_mode_; }
+
  private:
   v8::Isolate* isolate_;
+  std::unique_ptr<v8::SnapshotCreator> snapshot_creator_;
   std::unique_ptr<PerIsolateData> isolate_data_;
   std::unique_ptr<RunMicrotasksObserver> task_observer_;
   std::unique_ptr<V8IsolateMemoryDumpProvider> isolate_memory_dump_provider_;
   AccessMode access_mode_;
+  v8::StartupData startup_data_;
+  V8ContextMode v8_context_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(IsolateHolder);
 };
 
 }  // namespace gin
 
 #endif  // GIN_PUBLIC_ISOLATE_HOLDER_H_