Use a DownloadRequestHandle pointer in construction to allow mocking for tests.

content/browser/download/download_file_unittest.cc

Index: content/browser/download/download_file_unittest.cc
diff --git a/content/browser/download/download_file_unittest.cc b/content/browser/download/download_file_unittest.cc
index e91eabb2e4e5e7dd5300d7c1e42c3d743d5ec417..42288e0ec9e13a03ada1ed73865ec864e7aa8ae6 100644
--- a/content/browser/download/download_file_unittest.cc
+++ b/content/browser/download/download_file_unittest.cc
@@ -71,7 +71,8 @@ class DownloadFileTest : public testing::Test {
     // info.request_handle default constructed to null.
     info.save_info.file_stream = file_stream_;
     file->reset(
-        new DownloadFile(&info, DownloadRequestHandle(), download_manager_));
+        new DownloadFile(&info, new DownloadRequestHandle(),
+                         download_manager_));
   }
 
   virtual void DestroyDownloadFile(scoped_ptr<DownloadFile>* file, int offset) {