Adds the possibility of setting a Code object as the callback of a FunctionTemplate.

src/ic/mips64/handler-compiler-mips64.cc

Index: src/ic/mips64/handler-compiler-mips64.cc
diff --git a/src/ic/mips64/handler-compiler-mips64.cc b/src/ic/mips64/handler-compiler-mips64.cc
index 46ef13caac1e74bb7be3965e1d0102b10625c150..a3cfbd537e02fcb28f2dcbd764ca9abb7459a778 100644
--- a/src/ic/mips64/handler-compiler-mips64.cc
+++ b/src/ic/mips64/handler-compiler-mips64.cc
@@ -284,6 +284,13 @@ void PropertyHandlerCompiler::GenerateApiAccessorCall(
     __ ld(data, FieldMemOperand(data, FunctionTemplateInfo::kCallCodeOffset));
     __ ld(data, FieldMemOperand(data, CallHandlerInfo::kDataOffset));
   }
+
+  if (api_call_info->fast_handler()->IsCode()) {
+    // Just tail call into the fast handler if present.
+    __ Jump(handle(Code::cast(api_call_info->fast_handler())),
+            RelocInfo::CODE_TARGET);
+    return;
+  }
   // Put api_function_address in place.
   Address function_address = v8::ToCData<Address>(api_call_info->callback());
   ApiFunction fun(function_address);