Use idle time to make progress on scheduled compilation jobs

src/compiler-dispatcher/compiler-dispatcher-job.cc

Index: src/compiler-dispatcher/compiler-dispatcher-job.cc
diff --git a/src/compiler-dispatcher/compiler-dispatcher-job.cc b/src/compiler-dispatcher/compiler-dispatcher-job.cc
index b9e956caadde172d2c0db335d683f4a7f4c0f521..0513b18499412c115db18a6415522428b87077ff 100644
--- a/src/compiler-dispatcher/compiler-dispatcher-job.cc
+++ b/src/compiler-dispatcher/compiler-dispatcher-job.cc
@@ -263,5 +263,36 @@ void CompilerDispatcherJob::ResetOnMainThread() {
   status_ = CompileJobStatus::kInitial;
 }
 
+double CompilerDispatcherJob::EstimateRuntimeOfNextStepInMs() const {
+  switch (status_) {
+    case CompileJobStatus::kInitial:
+      return tracer_->EstimatePrepareToParseInMs();
+
+    case CompileJobStatus::kReadyToParse:
+      return tracer_->EstimateParseInMs(parse_info_->end_position() -
+                                        parse_info_->start_position());
+
+    case CompileJobStatus::kParsed:
+      return tracer_->EstimateFinalizeParsingInMs();
+
+    case CompileJobStatus::kReadyToAnalyse:
+      return tracer_->EstimatePrepareToCompileInMs();
+
+    case CompileJobStatus::kReadyToCompile:
+      return tracer_->EstimateCompileInMs(
+          parse_info_->literal()->ast_node_count());
+
+    case CompileJobStatus::kCompiled:
+      return tracer_->EstimateFinalizeCompilingInMs();
+
+    case CompileJobStatus::kFailed:
+    case CompileJobStatus::kDone:
+      return 0.0;
+  }
+
+  UNREACHABLE();
+  return 0.0;
+}
+
 }  // namespace internal
 }  // namespace v8