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

chrome/installer/util/google_update_settings.cc

Index: chrome/installer/util/google_update_settings.cc
diff --git a/chrome/installer/util/google_update_settings.cc b/chrome/installer/util/google_update_settings.cc
index 2550349daadfa4f9357a5daf50d9ae94e7c4f3ee..3c535f1bb4640dddd60a74b4b3bc5ec88850e77f 100644
--- a/chrome/installer/util/google_update_settings.cc
+++ b/chrome/installer/util/google_update_settings.cc
@@ -585,7 +585,8 @@ base::string16 GoogleUpdateSettings::GetUninstallCommandLine(
   return cmd_line;
 }
 
-Version GoogleUpdateSettings::GetGoogleUpdateVersion(bool system_install) {
+base::Version GoogleUpdateSettings::GetGoogleUpdateVersion(
+    bool system_install) {
   const HKEY root_key = system_install ? HKEY_LOCAL_MACHINE : HKEY_CURRENT_USER;
   base::string16 version;
   RegKey key;
@@ -595,10 +596,10 @@ Version GoogleUpdateSettings::GetGoogleUpdateVersion(bool system_install) {
                KEY_QUERY_VALUE) == ERROR_SUCCESS &&
       key.ReadValue(google_update::kRegGoogleUpdateVersion,
                     &version) == ERROR_SUCCESS) {
-    return Version(UTF16ToUTF8(version));
+    return base::Version(UTF16ToUTF8(version));
   }
 
-  return Version();
+  return base::Version();
 }
 
 base::Time GoogleUpdateSettings::GetGoogleUpdateLastStartedAU(