Clean up Android DownloadManager code as most download now go through Chrome Network stack

chrome/browser/android/download/mock_download_controller.cc

Index: chrome/browser/android/download/mock_download_controller.cc
diff --git a/chrome/browser/android/download/mock_download_controller.cc b/chrome/browser/android/download/mock_download_controller.cc
index 85b680a362f9b471af07d64af3dd71c46b4f2e7d..df198c6cd9a9c5dc6ef1241ae896207a74511397 100644
--- a/chrome/browser/android/download/mock_download_controller.cc
+++ b/chrome/browser/android/download/mock_download_controller.cc
@@ -17,11 +17,6 @@ MockDownloadController::MockDownloadController()
 
 MockDownloadController::~MockDownloadController() {}
 
-void MockDownloadController::CreateGETDownload(
-    const content::ResourceRequestInfo::WebContentsGetter& wc_getter,
-    bool must_download, const DownloadInfo& info) {
-}
-
 void MockDownloadController::OnDownloadStarted(
     content::DownloadItem* download_item) {
 }