Revert of base: Remove using:: declaration from version.h header.

chrome/browser/plugins/plugin_metadata_unittest.cc

Index: chrome/browser/plugins/plugin_metadata_unittest.cc
diff --git a/chrome/browser/plugins/plugin_metadata_unittest.cc b/chrome/browser/plugins/plugin_metadata_unittest.cc
index 25748e7b23f6ad4d5964c554e13e588e214cc202..fe9e2e659beb42d202affee3fa325a678cfc8580 100644
--- a/chrome/browser/plugins/plugin_metadata_unittest.cc
+++ b/chrome/browser/plugins/plugin_metadata_unittest.cc
@@ -41,9 +41,9 @@
   EXPECT_EQ(kRequiresAuthorization,
             GetSecurityStatus(&plugin_metadata, "1.2.3"));
 
-  plugin_metadata.AddVersion(base::Version("9.4.1"), kRequiresAuthorization);
-  plugin_metadata.AddVersion(base::Version("10"), kOutOfDate);
-  plugin_metadata.AddVersion(base::Version("10.2.1"), kUpToDate);
+  plugin_metadata.AddVersion(Version("9.4.1"), kRequiresAuthorization);
+  plugin_metadata.AddVersion(Version("10"), kOutOfDate);
+  plugin_metadata.AddVersion(Version("10.2.1"), kUpToDate);
 
   // Invalid version.
   EXPECT_EQ(kOutOfDate, GetSecurityStatus(&plugin_metadata, "foo"));