[crankshaft] Support ES6 tail call elimination.

src/arm64/macro-assembler-arm64.h

Index: src/arm64/macro-assembler-arm64.h
diff --git a/src/arm64/macro-assembler-arm64.h b/src/arm64/macro-assembler-arm64.h
index 5c8fe40b8098f391b14b25435d7b0d5f7e383a08..2a173de82aa0bece816d7c2718f43ad5a1c3dbfd 100644
--- a/src/arm64/macro-assembler-arm64.h
+++ b/src/arm64/macro-assembler-arm64.h
@@ -1166,6 +1166,15 @@ class MacroAssembler : public Assembler {
                       RelocInfo::Mode rmode = RelocInfo::CODE_TARGET,
                       TypeFeedbackId ast_id = TypeFeedbackId::None());
 
+  // Removes current frame and its arguments from the stack preserving
+  // the arguments and a return address pushed to the stack for the next call.
+  // Both |callee_args_count| and |caller_args_count_reg| do not include
+  // receiver. |callee_args_count| is not modified, |caller_args_count_reg|
+  // is trashed.
+  void PrepareForTailCall(const ParameterCount& callee_args_count,
+                          Register caller_args_count_reg, Register scratch0,
+                          Register scratch1);
+
   // Registers used through the invocation chain are hard-coded.
   // We force passing the parameters to ensure the contracts are correctly
   // honoured by the caller.