[gin] Fingerprint the V8 snapshot files on Windows and verify before loading the snapshot.

gin/public/isolate_holder.h

Index: gin/public/isolate_holder.h
diff --git a/gin/public/isolate_holder.h b/gin/public/isolate_holder.h
index b12734c4413c377ebcd6318b41fddd2b3ba721dd..ccaf8dafdfd5fbb3b2c30448008fef415dee4b24 100644
--- a/gin/public/isolate_holder.h
+++ b/gin/public/isolate_holder.h
@@ -51,16 +51,24 @@ class GIN_EXPORT IsolateHolder {
   // thread.
   void RemoveRunMicrotasksObserver();
 
-#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
   static bool LoadV8SnapshotFD(int natives_fd, int snapshot_fd);
+#if defined(OS_WIN)
+  static bool LoadAndVerifyV8Snapshot();
+#else
   static bool LoadV8Snapshot();
-#endif  // V8_USE_EXTERNAL_STARTUP_DATA
+#endif  // defined(OS_WIN)
+#endif  // defined(V8_USE_EXTERNAL_STARTUP_DATA)
   static void GetV8ExternalSnapshotData(const char** natives_data_out,
                                         int* natives_size_out,
                                         const char** snapshot_data_out,
                                         int* snapshot_size_out);
 
  private:
+#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
+  static bool LoadV8SnapshotCommon();
+#endif  // defined(V8_USE_EXTERNAL_STARTUP_DATA)
+
   v8::Isolate* isolate_;
   scoped_ptr<PerIsolateData> isolate_data_;
   scoped_ptr<RunMicrotasksObserver> task_observer_;