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

chrome/browser/extensions/extension_service.cc

Index: chrome/browser/extensions/extension_service.cc
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index bdfb3333c476f00136ae57adb0b2b4007c6939ea..3ed97062a3d71adc4ad5c3b407eeadce3cb98493 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -1563,7 +1563,7 @@
 void ExtensionService::AddComponentExtension(const Extension* extension) {
   const std::string old_version_string(
       extension_prefs_->GetVersionString(extension->id()));
-  const base::Version old_version(old_version_string);
+  const Version old_version(old_version_string);
 
   VLOG(1) << "AddComponentExtension " << extension->name();
   if (!old_version.IsValid() || !old_version.Equals(*extension->version())) {
@@ -2134,13 +2134,13 @@
 }
 
 bool ExtensionService::OnExternalExtensionFileFound(
-    const std::string& id,
-    const base::Version* version,
-    const base::FilePath& path,
-    Manifest::Location location,
-    int creation_flags,
-    bool mark_acknowledged,
-    bool install_immediately) {
+         const std::string& id,
+         const Version* version,
+         const base::FilePath& path,
+         Manifest::Location location,
+         int creation_flags,
+         bool mark_acknowledged,
+         bool install_immediately) {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   CHECK(crx_file::id_util::IdIsValid(id));
   if (extension_prefs_->IsExternalExtensionUninstalled(id))