[turbofan] Change RawMachineAssembler to take a CallDescriptor instead of a MachineSignature.

src/compiler/raw-machine-assembler.cc

Index: src/compiler/raw-machine-assembler.cc
diff --git a/src/compiler/raw-machine-assembler.cc b/src/compiler/raw-machine-assembler.cc
index 3e87ef5d97a9006dc35e95f5ccc8c714de4c6695..1a3d6494e93d07225e9c304e5339ddf67738296c 100644
--- a/src/compiler/raw-machine-assembler.cc
+++ b/src/compiler/raw-machine-assembler.cc
@@ -12,16 +12,14 @@ namespace internal {
 namespace compiler {
 
 RawMachineAssembler::RawMachineAssembler(Isolate* isolate, Graph* graph,
-                                         const MachineSignature* machine_sig,
+                                         CallDescriptor* call_descriptor,
                                          MachineType word,
                                          MachineOperatorBuilder::Flags flags)
     : GraphBuilder(isolate, graph),
       schedule_(new (zone()) Schedule(zone())),
       machine_(zone(), word, flags),
       common_(zone()),
-      machine_sig_(machine_sig),
-      call_descriptor_(
-          Linkage::GetSimplifiedCDescriptor(graph->zone(), machine_sig)),
+      call_descriptor_(call_descriptor),
       parameters_(NULL),
       current_block_(schedule()->start()) {
   int param_count = static_cast<int>(parameter_count());