Allow content to get the system request context, a request context not tied to any profile.

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index c8f84c274e13d88c1d46ed1f53f0a5a1f93d0b2b..7e286d0163846a1d47fbc23067f86db452cdd1ff 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -745,6 +745,12 @@ ChromeContentBrowserClient::GetDefaultRequestContextDeprecatedCrBug64339() {
   return Profile::Deprecated::GetDefaultRequestContext();
 }
 
+net::URLRequestContextGetter*
+ChromeContentBrowserClient::GetSystemRequestContext() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  return g_browser_process->system_request_context();
+}
+
 #if defined(OS_LINUX)
 int ChromeContentBrowserClient::GetCrashSignalFD(
     const std::string& process_type) {