startup: Put it in chrome namespace.

chrome/browser/ui/cocoa/obsolete_os.cc

Index: chrome/browser/ui/cocoa/obsolete_os.cc
diff --git a/chrome/browser/ui/cocoa/obsolete_os.cc b/chrome/browser/ui/cocoa/obsolete_os.cc
index 388cf92cc5dbbcc55779485414a795bff3236d59..764bf1d5eac5994cb11fbaa6dfc77c65e9dd3b07 100644
--- a/chrome/browser/ui/cocoa/obsolete_os.cc
+++ b/chrome/browser/ui/cocoa/obsolete_os.cc
@@ -8,7 +8,7 @@
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 
-namespace browser {
+namespace chrome {
 
 string16 LocalizedObsoleteOSString() {
   // TODO(mark): Change kEndOfTheLine to true immediately prior to the last
@@ -21,4 +21,4 @@ string16 LocalizedObsoleteOSString() {
       l10n_util::GetStringUTF16(IDS_PRODUCT_NAME));
 }
 
-}  // namespace browser
+}  // namespace chrome