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

extensions/browser/updater/extension_downloader.cc

Index: extensions/browser/updater/extension_downloader.cc
diff --git a/extensions/browser/updater/extension_downloader.cc b/extensions/browser/updater/extension_downloader.cc
index eebe259dc6031062727fa411c9eccd3ac1a93fac..d1d6468b0c94dc866e49583767e2f0c9b1711bb4 100644
--- a/extensions/browser/updater/extension_downloader.cc
+++ b/extensions/browser/updater/extension_downloader.cc
@@ -146,9 +146,9 @@
 
 }  // namespace
 
-UpdateDetails::UpdateDetails(const std::string& id,
-                             const base::Version& version)
-    : id(id), version(version) {}
+UpdateDetails::UpdateDetails(const std::string& id, const Version& version)
+    : id(id), version(version) {
+}
 
 UpdateDetails::~UpdateDetails() {
 }
@@ -232,7 +232,7 @@
   // Use a zero version to ensure that a pending extension will always
   // be updated, and thus installed (assuming all extensions have
   // non-zero versions).
-  base::Version version("0.0.0.0");
+  Version version("0.0.0.0");
   DCHECK(version.IsValid());
 
   return AddExtensionData(id,
@@ -296,7 +296,7 @@
 
 bool ExtensionDownloader::AddExtensionData(
     const std::string& id,
-    const base::Version& version,
+    const Version& version,
     Manifest::Type extension_type,
     const GURL& extension_update_url,
     const std::string& update_url_data,
@@ -661,8 +661,8 @@
 
       // We should skip the version check if update was forced.
       if (!fetch_data.DidForceUpdate(id)) {
-        base::Version existing_version(version);
-        base::Version update_version(update->version);
+        Version existing_version(version);
+        Version update_version(update->version);
         if (!update_version.IsValid() ||
             update_version.CompareTo(existing_version) <= 0) {
           continue;
@@ -878,7 +878,7 @@
 
 void ExtensionDownloader::NotifyUpdateFound(const std::string& id,
                                             const std::string& version) {
-  UpdateDetails updateInfo(id, base::Version(version));
+  UpdateDetails updateInfo(id, Version(version));
   content::NotificationService::current()->Notify(
       extensions::NOTIFICATION_EXTENSION_UPDATE_FOUND,
       content::NotificationService::AllBrowserContextsAndSources(),