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 d536f7af66e3fcb91b49ab8d9be808e5f8b274f5..ccc44735779777744770eae09a0ac67fe909a1ae 100644
--- a/blimp/engine/common/blimp_browser_context.cc
+++ b/blimp/engine/common/blimp_browser_context.cc
@@ -97,6 +97,11 @@ BlimpBrowserContext::GetDownloadManagerDelegate() {
   return nullptr;
 }
 
+net::URLRequestContextGetter* BlimpBrowserContext::GetSystemRequestContext() {
+  system_context_getter_ = new BlimpSystemURLRequestContextGetter();

[mmenke, 2016/04/06 20:44:56]

if (!system_context_getter_)
  system_context_getter_ = new BlimpSystemURLRequestContextGetter();

URLRequestContexts are pretty heavy weight, so want to make sure we don't have
more than one hanging around at a time.

[Jess, 2016/04/06 21:00:52]

Done.

+  return system_context_getter_.get();
+}
+
 net::URLRequestContextGetter* BlimpBrowserContext::GetRequestContext() {
   return GetDefaultStoragePartition(this)->GetURLRequestContext();
 }