Pulled out instrumentation into its own class separate from trace.

This is in preparation for Ian's debugger changes. The instrumentation
still needs support for debugging, which I'll add later.

Change-Id: I29ce0af1ff2eaec8f6d2f54963263381363ebf72
diff --git a/src/object.cc b/src/object.cc
index cebbb2a..aaaa245 100644
--- a/src/object.cc
+++ b/src/object.cc
@@ -540,8 +540,8 @@
   Runtime* runtime = Runtime::Current();
   const void* code = m->GetCode();
   // Peel off any method tracing trampoline.
-  if (runtime->IsMethodTracingActive() && runtime->GetTracer()->GetSavedCodeFromMap(m) != NULL) {
-    code = runtime->GetTracer()->GetSavedCodeFromMap(m);
+  if (runtime->IsMethodTracingActive() && runtime->GetInstrumentation()->GetSavedCodeFromMap(m) != NULL) {
+    code = runtime->GetInstrumentation()->GetSavedCodeFromMap(m);
   }
   // Peel off any resolution stub.
   if (code == runtime->GetResolutionStubArray(Runtime::kStaticMethod)->GetData()) {