Make iOS main() functions normal.

The weird foo_mains are no longer needed when we build with GN.

CQ_INCLUDE_TRYBOTS=skia.primary:Build-Mac-Clang-arm-Debug-iOS

Change-Id: Iae50696741e0dc277d96dda4968a1ae41cb17c8a
Reviewed-on: https://skia-review.googlesource.com/8064
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Stephan Altmueller <stephana@google.com>
diff --git a/bench/nanobench.cpp b/bench/nanobench.cpp
index 4e1da2b..0f1e482 100644
--- a/bench/nanobench.cpp
+++ b/bench/nanobench.cpp
@@ -1095,8 +1095,8 @@
     intentionallyLeaked->start();
 }
 
-int nanobench_main();
-int nanobench_main() {
+int main(int argc, char** argv) {
+    SkCommandLineFlags::Parse(argc, argv);
 #if defined(SK_BUILD_FOR_IOS)
     cd_Documents();
 #endif
@@ -1364,10 +1364,3 @@
 
     return 0;
 }
-
-#if !defined(SK_BUILD_FOR_IOS) || defined(NANOBENCH_DEFINE_MAIN)
-int main(int argc, char** argv) {
-    SkCommandLineFlags::Parse(argc, argv);
-    return nanobench_main();
-}
-#endif