chrome_exe_main: name os-specific files according to naming pattern

chrome/app/chrome_exe_main_gtk.cc

Index: chrome/app/chrome_exe_main_gtk.cc
diff --git a/chrome/app/chrome_exe_main_gtk.cc b/chrome/app/chrome_exe_main_gtk.cc
index f7f8485d58d6e274ddb6a36bccbd6ee1139e6219..35764af33521cfaa69d868767ada7657fe1448a5 100644
--- a/chrome/app/chrome_exe_main_gtk.cc
+++ b/chrome/app/chrome_exe_main_gtk.cc
@@ -12,9 +12,9 @@
 // order to make it easy to update the app from GoogleUpdate. We don't need
 // that extra layer with on linux.
 //
-// TODO(tc): This is similar to chrome_exe_main.mm.  After it's more clear what
-// needs to go here, we should evaluate whether or not to merge this file with
-// chrome_exe_main.mm.
+// TODO(tc): This is similar to chrome_exe_main_mac.mm.  After it's
+// more clear what needs to go here, we should evaluate whether or not
+// to merge this file with chrome_exe_main_mac.mm.
 
 extern "C" {
 int ChromeMain(int argc, const char** argv);