Creates BackgroundShell and uses it in test

mojo/shell/standalone/context.cc

Index: mojo/shell/standalone/context.cc
diff --git a/mojo/shell/standalone/context.cc b/mojo/shell/standalone/context.cc
index 41a003ff755bf2070e6cf045f032a3ec4eaf6637..ed2c364bcdd7b3a6408688a17454f9a84a155a8f 100644
--- a/mojo/shell/standalone/context.cc
+++ b/mojo/shell/standalone/context.cc
@@ -13,7 +13,6 @@
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
-#include "base/i18n/icu_util.h"
 #include "base/lazy_instance.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
@@ -199,10 +198,6 @@ void Context::Init(const base::FilePath& shell_file_root) {
         "mojo_runner.trace");
   }
 
-  // ICU data is a thing every part of the system needs. This here warms
-  // up the copy of ICU in the mojo runner.
-  CHECK(base::i18n::InitializeICU());
-
   EnsureEmbedderIsInitialized();
   task_runners_.reset(
       new TaskRunners(base::MessageLoop::current()->task_runner()));