Add a SafeMap equivalent to std::map but without the error-prone operator[].

Change-Id: Iae5ba2091c55a34dbd1005cf3d25fce2a8d5c1f9
diff --git a/src/compiler/codegen/arm/Thumb2/Gen.cc b/src/compiler/codegen/arm/Thumb2/Gen.cc
index fa51266..5451d57 100644
--- a/src/compiler/codegen/arm/Thumb2/Gen.cc
+++ b/src/compiler/codegen/arm/Thumb2/Gen.cc
@@ -133,8 +133,7 @@
        oatGetDalvikDisassembly(cUnit, mir->dalvikInsn, "") : NULL;
     boundaryLIR = newLIR1(cUnit, kPseudoDalvikByteCodeBoundary,
                           (intptr_t) instStr);
-    cUnit->boundaryMap.insert(std::make_pair(mir->offset,
-                             (LIR*)boundaryLIR));
+    cUnit->boundaryMap.Put(mir->offset, boundaryLIR);
     /* Don't generate the SSA annotation unless verbose mode is on */
     if (cUnit->printMe && mir->ssaRep) {
         char* ssaString = oatGetSSAString(cUnit, mir->ssaRep);