Remove RuntimeAPIDelegate::GetPreviousVersion.

chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc

Index: chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc
diff --git a/chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc b/chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc
index 0aa9c6a2a71d7d2cfd652acb1b370fa2ffddbc38..d4c0b762a4619ee522d867aa3f8196b906b0e510 100644
--- a/chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc
+++ b/chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc
@@ -170,17 +170,6 @@ void ChromeRuntimeAPIDelegate::RemoveUpdateObserver(
   }
 }
 
-base::Version ChromeRuntimeAPIDelegate::GetPreviousExtensionVersion(
-    const Extension* extension) {
-  // Get the previous version to check if this is an upgrade.
-  ExtensionService* service =
-      ExtensionSystem::Get(browser_context_)->extension_service();
-  const Extension* old = service->GetExtensionById(extension->id(), true);
-  if (old)
-    return *old->version();
-  return base::Version();
-}
-
 void ChromeRuntimeAPIDelegate::ReloadExtension(
     const std::string& extension_id) {
   std::pair<base::TimeTicks, int>& reload_info =