Replace GetForProfile by Get{FileSystem,DriveAppRegistry,DriveService)ByProfile.

chrome/browser/chromeos/drive/download_handler.cc

Index: chrome/browser/chromeos/drive/download_handler.cc
diff --git a/chrome/browser/chromeos/drive/download_handler.cc b/chrome/browser/chromeos/drive/download_handler.cc
index 2dd6c0fd723046bc9598a7d88d94cc53f39603d7..9cc3738d251627d50f2fb8054e131d351e1f1c85 100644
--- a/chrome/browser/chromeos/drive/download_handler.cc
+++ b/chrome/browser/chromeos/drive/download_handler.cc
@@ -107,6 +107,8 @@ DownloadHandler::~DownloadHandler() {
 DownloadHandler* DownloadHandler::GetForProfile(Profile* profile) {
   DriveIntegrationService* integration_service =
       DriveIntegrationServiceFactory::FindForProfile(profile);
+  // TODO(hidehiko): FindForProfile will return the instance even if Drive is
+  // disabled. Needs to check the state. crbug.com/284972.
   return integration_service ? integration_service->download_handler() : NULL;
 }