`#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
diff --git a/chrome/renderer/renderer_webstoragearea_impl.h b/chrome/renderer/renderer_webstoragearea_impl.h
index 8a324c28d..532933b 100644
--- a/chrome/renderer/renderer_webstoragearea_impl.h
+++ b/chrome/renderer/renderer_webstoragearea_impl.h
@@ -4,6 +4,7 @@
 
 #ifndef CHROME_RENDERER_RENDERER_WEBSTORAGEAREA_IMPL_H_
 #define CHROME_RENDERER_RENDERER_WEBSTORAGEAREA_IMPL_H_
+#pragma once
 
 #include "base/basictypes.h"
 #include "base/string16.h"