Revert of [builtins] Introduce proper Float64Exp operator.

src/mips64/codegen-mips64.h

Index: src/mips64/codegen-mips64.h
diff --git a/src/mips64/codegen-mips64.h b/src/mips64/codegen-mips64.h
index a4f818425a9ec67b0b1d1a2764a2e3a74a1314eb..ad7abb30c559153336f9739ba96c88ad69e168cd 100644
--- a/src/mips64/codegen-mips64.h
+++ b/src/mips64/codegen-mips64.h
@@ -29,6 +29,23 @@
   DISALLOW_COPY_AND_ASSIGN(StringCharLoadGenerator);
 };
 
+
+class MathExpGenerator : public AllStatic {
+ public:
+  // Register input isn't modified. All other registers are clobbered.
+  static void EmitMathExp(MacroAssembler* masm,
+                          DoubleRegister input,
+                          DoubleRegister result,
+                          DoubleRegister double_scratch1,
+                          DoubleRegister double_scratch2,
+                          Register temp1,
+                          Register temp2,
+                          Register temp3);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MathExpGenerator);
+};
+
 }  // namespace internal
 }  // namespace v8