Revert of Make nanobench and dm be usable from Chromium build (patchset #5 id:80001 of https://codereview.chromium.org/657373002/)

Reason for revert:
Causing breakages on Mac build.

Original issue's description:
> Make nanobench and dm be usable from Chromium build
>
> Move the app logic for each app as follows:
>
> <app>.cpp -- the file which contains main(). Embedders that compile
> their own apps, such as ios shell, upcoming Chromium dm etc, do not use this.
>
> <app>_main.cpp -- the main logic of the Skia test application. This will be
> used by Skia -compiled apps as well as embedder -compiled apps.
>
> <app>_main.h -- the API for the main logic. This will be
> used by Skia -compiled apps as well as embedder -compiled apps.
>
> This way (the upcoming) Chromium dm can setup its Chromium-specific setup
> in custom main(), and then call dm_main(), without the need of any
> SK_BUILD_FOR_XXXX defines controlling whether the tool defines main or not.
>
> BUG=skia:2992
>
> Committed: https://skia.googlesource.com/skia/+/c092d3bdab5f723576cc0346cea3ee282a9cb444

TBR=mtklein@chromium.org,mtklein@google.com,borenet@google.com,kkinnunen@nvidia.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:2992

Review URL: https://codereview.chromium.org/724073002
diff --git a/bench/nanobench.cpp b/bench/nanobench.cpp
index baa109e..1f5ae60 100644
--- a/bench/nanobench.cpp
+++ b/bench/nanobench.cpp
@@ -572,7 +572,9 @@
     int fCurrentSKP;
 };
 
+int nanobench_main();
 int nanobench_main() {
+    SetupCrashHandler();
     SkAutoGraphics ag;
 
 #if SK_SUPPORT_GPU
@@ -750,3 +752,9 @@
     return 0;
 }
 
+#if !defined SK_BUILD_FOR_IOS
+int main(int argc, char** argv) {
+    SkCommandLineFlags::Parse(argc, argv);
+    return nanobench_main();
+}
+#endif
diff --git a/bench/nanobench.h b/bench/nanobench.h
deleted file mode 100644
index 4616747..0000000
--- a/bench/nanobench.h
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * Copyright 2014 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-#ifndef nanobench_DEFINED
-#define nanobench_DEFINED
-
-// API for nanobench app.
-int nanobench_main();
-
-#endif
diff --git a/bench/nanobench_main.cpp b/bench/nanobench_main.cpp
deleted file mode 100644
index a598adc..0000000
--- a/bench/nanobench_main.cpp
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * Copyright 2014 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-
-#include "CrashHandler.h"
-#include "SkCommandLineFlags.h"
-#include "nanobench.h"
-
-int main(int argc, char * const argv[]) {
-    SetupCrashHandler();
-    SkCommandLineFlags::Parse(argc, const_cast<char**>(argv));
-    return nanobench_main();
-
-}