Use timer task runner for V8PerIsolate tasks

net/proxy/proxy_resolver_v8.cc

Index: net/proxy/proxy_resolver_v8.cc
diff --git a/net/proxy/proxy_resolver_v8.cc b/net/proxy/proxy_resolver_v8.cc
index 16ad61f742407697a94edeabd1da4de96300130f..a54fa69d0b50707e870b7fc874f284073ca5d0a7 100644
--- a/net/proxy/proxy_resolver_v8.cc
+++ b/net/proxy/proxy_resolver_v8.cc
@@ -18,6 +18,7 @@
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/lock.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "gin/array_buffer.h"
 #include "gin/public/isolate_holder.h"
 #include "gin/v8_initializer.h"
@@ -391,7 +392,8 @@ class SharedIsolateFactory {
         has_initialized_v8_ = true;
       }
 
-      holder_.reset(new gin::IsolateHolder(gin::IsolateHolder::kUseLocker));
+      holder_.reset(new gin::IsolateHolder(base::ThreadTaskRunnerHandle::Get(),
+                                           gin::IsolateHolder::kUseLocker));
     }
 
     return holder_->isolate();