Add parallel recompilation time to histogram and plot execution pause times.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index 1ff92f19606943f5c29b5cdf8076adc723ed81c5..c9d45978ab9be6bbf1e71b4f8784f9332f5309ca 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -852,6 +852,8 @@ void Compiler::RecompileParallel(Handle<JSFunction> closure) {
   ASSERT(closure->IsMarkedForParallelRecompilation());
 
   Isolate* isolate = closure->GetIsolate();
+  HistogramTimerScope timer(isolate->counters()->compile_parallel());
+
   if (!isolate->optimizing_compiler_thread()->IsQueueAvailable()) {
     if (FLAG_trace_parallel_recompilation) {
       PrintF("  ** Compilation queue, will retry opting on next run.\n");
@@ -860,7 +862,7 @@ void Compiler::RecompileParallel(Handle<JSFunction> closure) {
   }
 
   SmartPointer<CompilationInfo> info(new CompilationInfoWithZone(closure));
-  VMState state(isolate, PARALLEL_COMPILER_PROLOGUE);
+  VMState state(isolate, PARALLEL_COMPILER);
   PostponeInterruptsScope postpone(isolate);
 
   Handle<SharedFunctionInfo> shared = info->shared_info();
@@ -908,6 +910,9 @@ void Compiler::RecompileParallel(Handle<JSFunction> closure) {
 
 void Compiler::InstallOptimizedCode(OptimizingCompiler* optimizing_compiler) {
   SmartPointer<CompilationInfo> info(optimizing_compiler->info());
+  Isolate* isolate = info->isolate();
+  VMState state(isolate, PARALLEL_COMPILER);
+  HistogramTimerScope timer(isolate->counters()->compile_parallel());
   // If crankshaft succeeded, install the optimized code else install
   // the unoptimized code.
   OptimizingCompiler::Status status = optimizing_compiler->last_status();