[Bindings] Create and use V8 context snapshots

pdf/pdfium/pdfium_engine.cc

Index: pdf/pdfium/pdfium_engine.cc
diff --git a/pdf/pdfium/pdfium_engine.cc b/pdf/pdfium/pdfium_engine.cc
index 28e80d07ef888662aa6eff8681f948d0b3282407..570171189401ae5bec85fb3a76b3bc62403870c4 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -597,8 +597,8 @@ void SetUpV8() {
                                  gin::IsolateHolder::kStableV8Extras,
                                  gin::ArrayBufferAllocator::SharedInstance());
   DCHECK(!g_isolate_holder);
-  g_isolate_holder = new gin::IsolateHolder(base::ThreadTaskRunnerHandle::Get(),
-                                            gin::IsolateHolder::kSingleThread);
+  g_isolate_holder =
+      new gin::IsolateHolder(base::ThreadTaskRunnerHandle::Get());

[Yuki, 2017/06/20 14:20:10]

Is this a good change?  It seems better to explicitly pass kSingleThread rather
than implicitly assuming kSingleThread.

[peria, 2017/06/21 07:19:15]

Done.

   g_isolate_holder->isolate()->Enter();
 }