ppapi: PPB_VpnProvider: Implement Service Helper

content/public/browser/content_browser_client.h

Index: content/public/browser/content_browser_client.h
diff --git a/content/public/browser/content_browser_client.h b/content/public/browser/content_browser_client.h
index 493cb42a3d185296c1e46b195e749016074f4b62..5141792f142028c3cc8bfbf4f9f65d5bda4f8c9f 100644
--- a/content/public/browser/content_browser_client.h
+++ b/content/public/browser/content_browser_client.h
@@ -120,6 +120,7 @@ class ServiceRegistry;
 class SiteInstance;
 class SpeechRecognitionManagerDelegate;
 class TracingDelegate;
+class VpnServiceProxy;
 class WebContents;
 class WebContentsViewDelegate;
 struct MainFunctionParams;
@@ -587,6 +588,11 @@ class CONTENT_EXPORT ContentBrowserClient {
   virtual bool IsPepperVpnProviderAPIAllowed(BrowserContext* browser_context,
                                              const GURL& url);
 
+  // Creates a new VpnServiceProxy. The caller owns the returned value. It's
+  // valid to return nullptr.
+  virtual std::unique_ptr<VpnServiceProxy> GetVpnServiceProxy(
+      BrowserContext* browser_context);
+
   // Returns an implementation of a file selecition policy. Can return nullptr.
   virtual ui::SelectFilePolicy* CreateSelectFilePolicy(
       WebContents* web_contents);