Reland "Disable the CompilerDispatcher if we don't have idle time"

src/compiler-dispatcher/compiler-dispatcher.h

 // Copyright 2016 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_COMPILER_DISPATCHER_COMPILER_DISPATCHER_H_
 #define V8_COMPILER_DISPATCHER_COMPILER_DISPATCHER_H_
 
 #include <map>
 #include <memory>
 #include <utility>
@@ skipping 43 matching lines @@
   void AbortAll(BlockingBehavior blocking);
 
  private:
   FRIEND_TEST(CompilerDispatcherTest, IdleTaskSmallIdleTime);
 
   typedef std::multimap<std::pair<int, int>,
                         std::unique_ptr<CompilerDispatcherJob>>
       JobMap;
   class IdleTask;
 
+  bool IsEnabled() const;
   JobMap::const_iterator GetJobFor(Handle<SharedFunctionInfo> shared) const;
   void ScheduleIdleTaskIfNeeded();
   void DoIdleWork(double deadline_in_seconds);
 
   Isolate* isolate_;
   Platform* platform_;
   size_t max_stack_size_;
   std::unique_ptr<CompilerDispatcherTracer> tracer_;
 
   bool idle_task_scheduled_;
 
   // Mapping from (script id, function literal id) to job. We use a multimap,
   // as script id is not necessarily unique.
   JobMap jobs_;
 
   DISALLOW_COPY_AND_ASSIGN(CompilerDispatcher);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_DISPATCHER_COMPILER_DISPATCHER_H_