Add new system url request context getter to the blimp engine.

blimp/engine/common/blimp_browser_context.cc

Index: blimp/engine/common/blimp_browser_context.cc
diff --git a/blimp/engine/common/blimp_browser_context.cc b/blimp/engine/common/blimp_browser_context.cc
index 98a1201f24a78568bf2e1dbe7ceeb9c9f794a145..614bd494e253a59addf58722729a7856cf213293 100644
--- a/blimp/engine/common/blimp_browser_context.cc
+++ b/blimp/engine/common/blimp_browser_context.cc
@@ -97,6 +97,14 @@ BlimpBrowserContext::GetDownloadManagerDelegate() {
   return nullptr;
 }
 
+net::URLRequestContextGetter*
+BlimpBrowserContext::GetSystemRequestContextGetter() {
+  if (!system_context_getter_) {
+    system_context_getter_ = new BlimpSystemURLRequestContextGetter();
+  }
+  return system_context_getter_.get();
+}
+
 net::URLRequestContextGetter* BlimpBrowserContext::GetRequestContext() {
   return GetDefaultStoragePartition(this)->GetURLRequestContext();
 }