Add OptimizingCompilerStats to the CodeGenerator class.

Just refactoring, not yet used, but will be used by the incoming patch
series and future CodeGen specific stats.

Change-Id: I7d20489907b82678120518a77bdab9c4cc58f937
Signed-off-by: Serban Constantinescu <serban.constantinescu@linaro.org>
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 820ec78..0ea95e8 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -559,7 +559,8 @@
 static constexpr Register kFakeReturnRegister = Register(kLastCpuRegister + 1);
 CodeGeneratorX86_64::CodeGeneratorX86_64(HGraph* graph,
                 const X86_64InstructionSetFeatures& isa_features,
-                const CompilerOptions& compiler_options)
+                const CompilerOptions& compiler_options,
+                OptimizingCompilerStats* stats)
       : CodeGenerator(graph,
                       kNumberOfCpuRegisters,
                       kNumberOfFloatRegisters,
@@ -569,7 +570,8 @@
                           | (1 << kFakeReturnRegister),
                       ComputeRegisterMask(reinterpret_cast<const int*>(kFpuCalleeSaves),
                                           arraysize(kFpuCalleeSaves)),
-                      compiler_options),
+                      compiler_options,
+                      stats),
         block_labels_(graph->GetArena(), 0),
         location_builder_(graph, this),
         instruction_visitor_(graph, this),