Refactor all instances of `typedef y x` to the C++11 `using x = y` syntax.

src/IceTimerTree.cpp

 //===- subzero/src/IceTimerTree.cpp - Pass timer defs ---------------------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 202 matching lines @@
   LeafTimes.assign(LeafTimes.size(), 0);
   LeafCounts.assign(LeafCounts.size(), 0);
   for (TimerTreeNode &Node : Nodes) {
     Node.Time = 0;
     Node.UpdateCount = 0;
   }
 }
 
 namespace {
 
-typedef std::multimap<double, IceString> DumpMapType;
+using DumpMapType = std::multimap<double, IceString>;
 
 // Dump the Map items in reverse order of their time contribution.
 void dumpHelper(Ostream &Str, const DumpMapType &Map, double TotalTime) {
   if (!BuildDefs::dump())
     return;
   for (auto &I : reverse_range(Map)) {
     char buf[80];
     snprintf(buf, llvm::array_lengthof(buf), "  %10.6f (%4.1f%%): ", I.first,
              I.first * 100 / TotalTime);
     Str << buf << I.second << "\n";
@@ skipping 69 matching lines @@
   dumpHelper(Str, FlatMap, TotalTime);
   Str << "Number of timer updates: " << StateChangeCount << "\n";
 }
 
 double TimerStack::timestamp() {
   // TODO: Implement in terms of std::chrono for C++11.
   return llvm::TimeRecord::getCurrentTime(false).getWallTime();
 }
 
 } // end of namespace Ice