Update all users of base::Version to explicitly specify the namespace, and clean up the header.

chrome/browser/extensions/extension_sync_data.h

Index: chrome/browser/extensions/extension_sync_data.h
diff --git a/chrome/browser/extensions/extension_sync_data.h b/chrome/browser/extensions/extension_sync_data.h
index 8fbe73afcce3cc89d3794736ad19fd790e675edf..1f897948a0a2f6a41f6b2037a9a5c630bdf71d89 100644
--- a/chrome/browser/extensions/extension_sync_data.h
+++ b/chrome/browser/extensions/extension_sync_data.h
@@ -59,7 +59,7 @@ class ExtensionSyncData {
 
   // Version-dependent properties (i.e., should be used only when the
   // version of the currenty-installed extension matches |version|).
-  const Version& version() const { return version_; }
+  const base::Version& version() const { return version_; }
   const GURL& update_url() const { return update_url_; }
   // Used only for debugging.
   const std::string& name() const { return name_; }
@@ -72,7 +72,7 @@ class ExtensionSyncData {
   bool uninstalled_;
   bool enabled_;
   bool incognito_enabled_;
-  Version version_;
+  base::Version version_;
   GURL update_url_;
   std::string name_;
 };