downloads: prevent "Clear all" from removing in progress downloads

content/browser/download/download_item_impl.cc

Index: content/browser/download/download_item_impl.cc
diff --git a/content/browser/download/download_item_impl.cc b/content/browser/download/download_item_impl.cc
index 753656fee29249a461a1830456242bbddf1e0d26..38f9e1ab89d98111eddd549e6c39cb9194a46b93 100644
--- a/content/browser/download/download_item_impl.cc
+++ b/content/browser/download/download_item_impl.cc
@@ -414,7 +414,8 @@ void DownloadItemImpl::Cancel(bool user_cancel) {
   if (!is_save_package_download_ && download_file_)
     ReleaseDownloadFile(true);
 
-  if (state_ == IN_PROGRESS_INTERNAL) {
+  // |request_handle_| may be NULL during tests.
+  if (state_ == IN_PROGRESS_INTERNAL && request_handle_) {

[benjhayden, 2014/12/11 23:36:24]

Should this be checked everywhere that request_handle_ is used?
Or would it be possible to construct a request handle, either real or mock?

[Dan Beam, 2014/12/12 00:07:02]

we talked about this on chat -- adding a way to mock something internal to the
download manager (a content/ feature) from here (chrome/) requires more effort
and fun than it's probably currently worth.  additionally, the more
|request_handle_ == NULL| checks I add, the less safe the code gets when it
*shouldn't* be null (which is currently only in this one case).

I've added a TODO() for now.

     // Cancel the originating URL request unless it's already been cancelled
     // by interrupt.
     request_handle_->CancelRequest();