Use idle time to make progress on scheduled compilation jobs

src/compiler-dispatcher/compiler-dispatcher-job.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_JOB_H_
 #define V8_COMPILER_DISPATCHER_COMPILER_DISPATCHER_JOB_H_
 
 #include <memory>
 
 #include "src/base/macros.h"
@@ skipping 65 matching lines @@
   // Transition from kReadyToCompile to kCompiled.
   void Compile();
 
   // Transition from kCompiled to kDone (or kFailed). Returns false when
   // transitioning to kFailed. In that case, an exception is pending.
   bool FinalizeCompilingOnMainThread();
 
   // Transition from any state to kInitial and free all resources.
   void ResetOnMainThread();
 
+  // Estimate how long the next step will take using the tracer.
+  double EstimateRuntimeOfNextStepInMs() const;
+
  private:
   FRIEND_TEST(CompilerDispatcherJobTest, ScopeChain);
 
   CompileJobStatus status_ = CompileJobStatus::kInitial;
   Isolate* isolate_;
   CompilerDispatcherTracer* tracer_;
   Handle<SharedFunctionInfo> shared_;  // Global handle.
   Handle<String> source_;        // Global handle.
   size_t max_stack_size_;
 
@@ skipping 12 matching lines @@
   bool can_parse_on_background_thread_;
   bool can_compile_on_background_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(CompilerDispatcherJob);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_DISPATCHER_COMPILER_DISPATCHER_JOB_H_