Replace std::tr1::shared_ptr by std::shared_ptr.

This patch replaces C++ Technical Report 1 additions to C++03 with
the newer C++11 name.

Includes and using statements updated accordingly.

BUG=None
TEST=Build and unittests.

Change-Id: I9bdad6d39684545c786f5c76fb598a15b557d6eb
Reviewed-on: https://chromium-review.googlesource.com/200665
Tested-by: Alex Deymo <deymo@chromium.org>
Reviewed-by: David Zeuthen <zeuthen@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>

subprocess.h

diff --git a/subprocess.h b/subprocess.h
index 9e64806..3a8424c 100644
--- a/subprocess.h
+++ b/subprocess.h
@@ -6,8 +6,8 @@
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_SUBPROCESS_H_
 
 #include <map>
+#include <memory>
 #include <string>
-#include <tr1/memory>
 #include <vector>
 
 #include <glib.h>
@@ -97,7 +97,7 @@
 
   // A map from the asynchronous subprocess tag (see Exec) to the subprocess
   // record structure for all active asynchronous subprocesses.
-  std::map<int, std::tr1::shared_ptr<SubprocessRecord> > subprocess_records_;
+  std::map<int, std::shared_ptr<SubprocessRecord> > subprocess_records_;
 
   DISALLOW_COPY_AND_ASSIGN(Subprocess);
 };