[cleanup] Fix use of deprecated GetFunction method

Use MaybeLocal version of GetFunction in SandboxStatusExtension as
original function is deprecated. Since the original code DCHECKs that
other failure can't happen, I've used the same pattern rather than
ToLocalChecked.

Bug: v8:7295, v8:8238
Change-Id: I29178794660dc7c5cf6d6bba0c617dfbbb37757d
Reviewed-on: https://chromium-review.googlesource.com/c/1348047Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611052}

chrome/renderer/sandbox_status_extension_android.cc

@@ -76,11 +76,16 @@ void SandboxStatusExtension::Install() {
 
   v8::Local<v8::Object> chrome =
       content::GetOrCreateChromeObject(isolate, context->Global());
-  bool success = chrome->Set(
-      gin::StringToSymbol(isolate, "getAndroidSandboxStatus"),
+  v8::Local<v8::Function> function;
+  bool success =
       gin::CreateFunctionTemplate(
           isolate, base::Bind(&SandboxStatusExtension::GetSandboxStatus, this))
-          ->GetFunction());
+          ->GetFunction(context)
+          .ToLocal(&function);
+  if (success) {
+    success = chrome->Set(
+        gin::StringToSymbol(isolate, "getAndroidSandboxStatus"), function);
+  }
   DCHECK(success);
 }