Revert three commits due to cpu-profiler failures

src/profiler/tick-sample.h

Index: src/profiler/tick-sample.h
diff --git a/src/profiler/tick-sample.h b/src/profiler/tick-sample.h
index df6d0cb0797b6c200550da62371f51d1544c9235..c7c42e63a28d10f6216d68179989247814e17d16 100644
--- a/src/profiler/tick-sample.h
+++ b/src/profiler/tick-sample.h
@@ -15,11 +15,21 @@ namespace internal {
 class Isolate;
 
 struct TickSample : public v8::TickSample {
+  TickSample() : v8::TickSample() {}
   void Init(Isolate* isolate, const v8::RegisterState& state,
             RecordCEntryFrame record_c_entry_frame, bool update_stats);
   base::TimeTicks timestamp;
 };
 
+#if defined(USE_SIMULATOR)
+class SimulatorHelper {
+ public:
+  // Returns true if register values were successfully retrieved
+  // from the simulator, otherwise returns false.
+  static bool FillRegisters(Isolate* isolate, v8::RegisterState* state);
+};
+#endif  // USE_SIMULATOR
+
 }  // namespace internal
 }  // namespace v8