[compiler] Add baseline tier to compilation pipeline.

src/runtime-profiler.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_RUNTIME_PROFILER_H_
 #define V8_RUNTIME_PROFILER_H_
 
 #include "src/allocation.h"
 
 namespace v8 {
-
-namespace base {
-class Semaphore;
-}
-
 namespace internal {
 
 class Isolate;
 class JSFunction;
-class Object;
 
 class RuntimeProfiler {
  public:
   explicit RuntimeProfiler(Isolate* isolate);
 
   void MarkCandidatesForOptimization();
 
   void NotifyICChanged() { any_ic_changed_ = true; }
 
   void AttemptOnStackReplacement(JSFunction* function, int nesting_levels = 1);
 
  private:
   void MaybeOptimizeFullCodegen(JSFunction* function, int frame_count,
                                 bool frame_optimized);
   void MaybeOptimizeIgnition(JSFunction* function, bool frame_optimized);
   void Optimize(JSFunction* function, const char* reason);
 
   bool CodeSizeOKForOSR(Code* shared_code);
 
   Isolate* isolate_;
 
   bool any_ic_changed_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_RUNTIME_PROFILER_H_