Don't delay creation of system URLRequestContext until first use

chrome/test/base/testing_io_thread_state.cc

Index: chrome/test/base/testing_io_thread_state.cc
diff --git a/chrome/test/base/testing_io_thread_state.cc b/chrome/test/base/testing_io_thread_state.cc
index 8e6ab8692af47b0b05377e05af5684b2f0b75ea6..c3c1205cd5066c5d30262b97b7c166ed591610f9 100644
--- a/chrome/test/base/testing_io_thread_state.cc
+++ b/chrome/test/base/testing_io_thread_state.cc
@@ -96,8 +96,7 @@ void TestingIOThreadState::Initialize(const base::Closure& done) {
 void TestingIOThreadState::Shutdown(const base::Closure& done) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  delete io_thread_state_->globals();
-  io_thread_state_->SetGlobalsForTesting(NULL);
+  io_thread_state_->CleanUp();

[mmenke, 2017/05/09 17:53:53]

This change is needed because now  system_proxy_config_service_ is initialized
in IOThread::Init, it's not destroyed when destroying globals, and on OSX the
proxy service DCHECKs that it's destroyed on the IOTHread, which normally
happens in IOThread::Cleanup.

   done.Run();
 }