Fix lifetime management of URLRequestContextGetter

I noticed this bug while adding persistent cookie storage.

brightray/browser/browser_context.cc

@@ -43,11 +43,11 @@ BrowserContext::~BrowserContext() {
 
 net::URLRequestContextGetter* BrowserContext::CreateRequestContext(content::ProtocolHandlerMap* protocol_handlers) {
   DCHECK(!url_request_getter_);
-  url_request_getter_.reset(new URLRequestContextGetter(
+  url_request_getter_ = new URLRequestContextGetter(
       GetPath(),
       content::BrowserThread::UnsafeGetMessageLoopForThread(content::BrowserThread::IO),
       content::BrowserThread::UnsafeGetMessageLoopForThread(content::BrowserThread::FILE),
-      protocol_handlers));
+      protocol_handlers);
   resource_context_->set_url_request_context_getter(url_request_getter_.get());
   return url_request_getter_.get();
 }

brightray/browser/browser_context.h

@@ -36,7 +36,7 @@ private:
   virtual quota::SpecialStoragePolicy* GetSpecialStoragePolicy() OVERRIDE;
 
   scoped_ptr<ResourceContext> resource_context_;
-  scoped_ptr<URLRequestContextGetter> url_request_getter_;
+  scoped_refptr<URLRequestContextGetter> url_request_getter_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserContext);
 };