Remove dead Android code from Cast content test launcher

Follow-up to
https://chromium-review.googlesource.com/c/chromium/src/+/1606402 which
moves CreateContentMainDelegate() under a !OS_ANDROID #ifdef.

Bug: 961849
Test: Compiled chromecast/app:test_support on Android.
Change-Id: I3b9cf531728407be1280d767f8573e2d9cf72c5b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1610751
Auto-Submit: Daniel Nicoara <dnicoara@chromium.org>
Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Commit-Queue: Daniel Nicoara <dnicoara@chromium.org>
Cr-Commit-Position: refs/heads/master@{#659470}

chromecast/app/cast_test_launcher.cc

@@ -7,6 +7,7 @@
 #include "base/system/sys_info.h"
 #include "base/test/launcher/test_launcher.h"
 #include "base/test/test_suite.h"
+#include "build/build_config.h"
 #include "chromecast/app/cast_main_delegate.h"
 #include "content/public/test/test_launcher.h"
 #include "ipc/ipc_channel.h"
@@ -34,9 +35,11 @@ class CastTestLauncherDelegate : public content::TestLauncherDelegate {
   }
 
  protected:
+#if !defined(OS_ANDROID)
   content::ContentMainDelegate* CreateContentMainDelegate() override {
     return new CastMainDelegate();
   }
+#endif  // defined(OS_ANDROID)
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CastTestLauncherDelegate);