Convert ContentMain to take a struct instead of parameters that vary depending on the platform.

content/shell/app/shell_main.cc

Index: content/shell/app/shell_main.cc
===================================================================
--- content/shell/app/shell_main.cc	(revision 255735)
+++ content/shell/app/shell_main.cc	(working copy)
@@ -20,7 +20,11 @@
   sandbox::SandboxInterfaceInfo sandbox_info = {0};
   content::InitializeSandboxInfo(&sandbox_info);
   content::ShellMainDelegate delegate;
-  return content::ContentMain(instance, &sandbox_info, &delegate);
+
+  content::ContentMainParams params(&delegate);
+  params.instance = instance;
+  params.sandbox_info = &sandbox_info;
+  return content::ContentMain(params);
 }
 
 #else
@@ -32,7 +36,10 @@
   return ::ContentMain(argc, argv);
 #else
   content::ShellMainDelegate delegate;
-  return content::ContentMain(argc, argv, &delegate);
+  content::ContentMainParams params(&delegate);
+  params.argc = argc;
+  params.argv = argv;
+  return content::ContentMain(params);
 #endif  // OS_MACOSX
 }