More profiler driven tweaks.

Make more code inlinable by moving to header files.
Use reserve on std::vectors to avoid reallocation.

Change-Id: I1bf67d32dd58ff5c06dec73a247fadc3de593e91
diff --git a/src/compiler/dex/mir_dataflow.cc b/src/compiler/dex/mir_dataflow.cc
index f65c9ae..0baf630 100644
--- a/src/compiler/dex/mir_dataflow.cc
+++ b/src/compiler/dex/mir_dataflow.cc
@@ -933,7 +933,7 @@
   SetNumSSARegs(ssa_reg + 1);
   ssa_base_vregs_->Insert(v_reg);
   ssa_subscripts_->Insert(subscript);
-  std::string ssa_name = GetSSAName(ssa_reg);
+  std::string ssa_name(GetSSAName(ssa_reg));
   char* name = static_cast<char*>(arena_->NewMem(ssa_name.length() + 1, false,
                                                  ArenaAllocator::kAllocDFInfo));
   strncpy(name, ssa_name.c_str(), ssa_name.length() + 1);