Add histogram timers for (de-)serialization during compilation.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index 644f7e9022e6a4066664782dc986b33168787dd7..d60cbd7ef784a993d7915bec697d549bc74e27c6 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -1051,6 +1051,7 @@ Handle<SharedFunctionInfo> Compiler::CompileScript(
     if (FLAG_serialize_toplevel &&
         compile_options == ScriptCompiler::kConsumeCodeCache &&
         !isolate->debug()->is_loaded()) {
+      HistogramTimerScope timer(isolate->counters()->compile_deserialize());
       return CodeSerializer::Deserialize(isolate, *cached_data, source);
     } else {
       maybe_result = compilation_cache->LookupScript(
@@ -1097,6 +1098,8 @@ Handle<SharedFunctionInfo> Compiler::CompileScript(
       compilation_cache->PutScript(source, context, result);
       if (FLAG_serialize_toplevel &&
           compile_options == ScriptCompiler::kProduceCodeCache) {
+        HistogramTimerScope histogram_timer(
+            isolate->counters()->compile_serialize());
         *cached_data = CodeSerializer::Serialize(isolate, result, source);
         if (FLAG_profile_deserialization) {
           PrintF("[Compiling and serializing %d bytes took %0.3f ms]\n",