Make closures optimizable by Crankshaft compiler.

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 54d54dd67ca9e880316a7824d06f9342c89abd16..1adca27d0f7f40e60a1f3da865894ec20b8ac39f 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -244,6 +244,11 @@ void LUnaryMathOperation::PrintDataTo(StringStream* stream) {
 }
 
 
+void LLoadContextSlot::PrintDataTo(StringStream* stream) {
+  stream->Add("(%d, %d)", context_chain_length(), slot_index());
+}
+
+
 void LCallKeyed::PrintDataTo(StringStream* stream) {
   stream->Add("[ecx] #%d / ", arity());
 }
@@ -1673,6 +1678,11 @@ LInstruction* LChunkBuilder::DoStoreGlobal(HStoreGlobal* instr) {
 }
 
 
+LInstruction* LChunkBuilder::DoLoadContextSlot(HLoadContextSlot* instr) {
+  return DefineAsRegister(new LLoadContextSlot);
+}
+
+
 LInstruction* LChunkBuilder::DoLoadNamedField(HLoadNamedField* instr) {
   return DefineAsRegister(
       new LLoadNamedField(UseRegisterAtStart(instr->object())));