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

chrome/browser/extensions/crx_installer.cc

Index: chrome/browser/extensions/crx_installer.cc
diff --git a/chrome/browser/extensions/crx_installer.cc b/chrome/browser/extensions/crx_installer.cc
index 50aa8916c0cbdac08902c1faa6f60af4a6fa5785..5516970716decfcf9a93cfee95af801059c45f0b 100644
--- a/chrome/browser/extensions/crx_installer.cc
+++ b/chrome/browser/extensions/crx_installer.cc
@@ -153,7 +153,7 @@ CrxInstaller::CrxInstaller(
     expected_id_ = approval->extension_id;
   }
   if (approval->minimum_version.get()) {
-    expected_version_.reset(new Version(*approval->minimum_version));
+    expected_version_.reset(new base::Version(*approval->minimum_version));
     expected_version_strict_checking_ = false;
   }
 
@@ -482,7 +482,7 @@ void CrxInstaller::CheckImportsAndRequirements() {
         SharedModuleInfo::GetImports(extension());
     std::vector<SharedModuleInfo::ImportInfo>::const_iterator i;
     for (i = imports.begin(); i != imports.end(); ++i) {
-      Version version_required(i->minimum_version);
+      base::Version version_required(i->minimum_version);
       const Extension* imported_module =
           service->GetExtensionById(i->extension_id, true);
       if (imported_module &&
@@ -660,7 +660,7 @@ void CrxInstaller::CompleteInstall() {
   DCHECK(installer_task_runner_->RunsTasksOnCurrentThread());
 
   if (!current_version_.empty()) {
-    Version current_version(current_version_);
+    base::Version current_version(current_version_);
     if (current_version.CompareTo(*(extension()->version())) > 0) {
       ReportFailureFromFileThread(
           CrxInstallerError(