[crankshaft] Support ES6 tail call elimination.

src/crankshaft/arm64/lithium-codegen-arm64.h

Index: src/crankshaft/arm64/lithium-codegen-arm64.h
diff --git a/src/crankshaft/arm64/lithium-codegen-arm64.h b/src/crankshaft/arm64/lithium-codegen-arm64.h
index cf7de10394e01940752493c32fb875d4d98f59dc..f67ad5ab5dbb88126e1839cbcf05cbbd1d817433 100644
--- a/src/crankshaft/arm64/lithium-codegen-arm64.h
+++ b/src/crankshaft/arm64/lithium-codegen-arm64.h
@@ -322,11 +322,14 @@ class LCodeGen: public LCodeGenBase {
                                LInstruction* instr,
                                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 x1.
   void CallKnownFunction(Handle<JSFunction> function,
                          int formal_parameter_count, int arity,
-                         LInstruction* instr);
+                         bool is_tail_call, LInstruction* instr);
 
   // Support for recording safepoint and position information.
   void RecordAndWritePosition(int position) override;