[cleanup] Fix use of deprecated v8::Handle class

Change deprecated v8::Handle to v8::Local.

Bug: v8:8238
Change-Id: Ic6fcf5f8aba221d2c48f11502656df88b1b84a24
Reviewed-on: https://chromium-review.googlesource.com/c/1348470Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610662}

chrome/renderer/searchbox/searchbox_extension.cc

@@ -1041,7 +1041,7 @@ void SearchBoxExtension::Install(blink::WebLocalFrame* frame) {
   if (newtabpage_controller.IsEmpty())
     return;
 
-  v8::Handle<v8::Object> chrome =
+  v8::Local<v8::Object> chrome =
       content::GetOrCreateChromeObject(isolate, context->Global());
   v8::Local<v8::Object> embedded_search = v8::Object::New(isolate);
   embedded_search