Put Filter into namespace net.

net/base/filter.h

Index: net/base/filter.h
diff --git a/net/base/filter.h b/net/base/filter.h
index f00e95ece4ae55205a6c9836133ecf236230e635..b8d87a3cfafbd7f6b5f79eb5f8d36cef248a3aeb 100644
--- a/net/base/filter.h
+++ b/net/base/filter.h
@@ -42,9 +42,8 @@
 class GURL;
 
 namespace net {
+
 class IOBuffer;
-class SdchFilterChainingTest;
-}
 
 //------------------------------------------------------------------------------
 // Define an interface class that allows access to contextual information
@@ -194,7 +193,7 @@ class Filter {
 
  protected:
   friend class GZipUnitTest;
-  friend class net::SdchFilterChainingTest;
+  friend class SdchFilterChainingTest;
 
   explicit Filter(const FilterContext& filter_context);
 
@@ -267,4 +266,6 @@ class Filter {
   DISALLOW_COPY_AND_ASSIGN(Filter);
 };
 
+}  // namespace net
+
 #endif  // NET_BASE_FILTER_H__