[crankshaft] Support ES6 tail call elimination.

src/crankshaft/ia32/lithium-codegen-ia32.h

Index: src/crankshaft/ia32/lithium-codegen-ia32.h
diff --git a/src/crankshaft/ia32/lithium-codegen-ia32.h b/src/crankshaft/ia32/lithium-codegen-ia32.h
index 4a521865969d2b2e2fcaec4e778d53b57740a9b1..bc61c9633908ec43cb459283f25d310ae503d24e 100644
--- a/src/crankshaft/ia32/lithium-codegen-ia32.h
+++ b/src/crankshaft/ia32/lithium-codegen-ia32.h
@@ -191,11 +191,14 @@ class LCodeGen: public LCodeGenBase {
 
   void LoadContextFromDeferred(LOperand* context);
 
+  void PrepareForTailCall(const ParameterCount& actual, Register scratch1,
+                          Register scratch2, Register scratch3);
+
   // Generate a direct call to a known function. Expects the function
   // to be in edi.
   void CallKnownFunction(Handle<JSFunction> function,
                          int formal_parameter_count, int arity,
-                         LInstruction* instr);
+                         bool is_tail_call, LInstruction* instr);
 
   void RecordSafepointWithLazyDeopt(LInstruction* instr,
                                     SafepointMode safepoint_mode);