Consistently use namespaced base::Version in extensions code.

chrome/browser/extensions/webstore_installer.cc

Index: chrome/browser/extensions/webstore_installer.cc
diff --git a/chrome/browser/extensions/webstore_installer.cc b/chrome/browser/extensions/webstore_installer.cc
index 1178c869b5cd008ed2560ad849021fa68fc17248..adb5e13c7f845e6d88b267f5d075607bfe1b00a8 100644
--- a/chrome/browser/extensions/webstore_installer.cc
+++ b/chrome/browser/extensions/webstore_installer.cc
@@ -414,7 +414,7 @@ void WebstoreInstaller::OnExtensionInstalled(
     CHECK_EQ(extension->id(), id_);
     ReportSuccess();
   } else {
-    const Version version_required(info.minimum_version);
+    const base::Version version_required(info.minimum_version);
     if (version_required.IsValid() &&
         extension->version()->CompareTo(version_required) < 0) {
       // It should not happen, CrxInstaller will make sure the version is
@@ -488,11 +488,10 @@ void WebstoreInstaller::OnDownloadStarted(
         Approval::CreateForSharedModule(profile_);
     const SharedModuleInfo::ImportInfo& info = pending_modules_.front();
     approval->extension_id = info.extension_id;
-    const Version version_required(info.minimum_version);
+    const base::Version version_required(info.minimum_version);
 
     if (version_required.IsValid()) {
-      approval->minimum_version.reset(
-          new Version(version_required));
+      approval->minimum_version.reset(new base::Version(version_required));
     }
     download_item_->SetUserData(kApprovalKey, approval.release());
   } else {