`#pragma once` for app, base, chrome, gfx, ipc, net, skia, views

BUG=50273
TEST=everything still builds, build is 10% faster on windows, same speed on mac/linux

TBR: erg

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@53716 0039d316-1c4b-4281-b951-d872f2087c98


CrOS-Libchrome-Original-Commit: 32b76eff6f630b9bcc0fc3f3bad826f3d1217dda
diff --git a/base/base_paths.h b/base/base_paths.h
index 6a8342e..0f9be04 100644
--- a/base/base_paths.h
+++ b/base/base_paths.h
@@ -4,6 +4,7 @@
 
 #ifndef BASE_BASE_PATHS_H_
 #define BASE_BASE_PATHS_H_
+#pragma once
 
 // This file declares path keys for the base module.  These can be used with
 // the PathService to access various special directories and files.