Added callback to DownloadUrl() so we can find download failures.

chrome/browser/download/download_test_observer.cc

Index: chrome/browser/download/download_test_observer.cc
diff --git a/chrome/browser/download/download_test_observer.cc b/chrome/browser/download/download_test_observer.cc
index 729d5bbc4e0846edf716a15b5c9af47247778ca3..3e7ac7067a398bbc15b5d01ba1475137d0fac6ab 100644
--- a/chrome/browser/download/download_test_observer.cc
+++ b/chrome/browser/download/download_test_observer.cc
@@ -341,3 +341,33 @@ void DownloadTestFlushObserver::PingIOThread(int cycle) {
         BrowserThread::UI, FROM_HERE, MessageLoop::QuitClosure());
   }
 }
+
+DownloadTestItemCreationObserver::DownloadTestItemCreationObserver(size_t count)
+    : expected_count_(count),
+      called_back_count_(0),
+      waiting_(false),
+      ALLOW_THIS_IN_INITIALIZER_LIST(callback_(base::Bind(
+          &DownloadTestItemCreationObserver::DownloadItemCreationCallback,
+          this))) {
+  creation_info_.resize(count);
+}
+
+void DownloadTestItemCreationObserver::WaitForDownloadItemCreation() {
+  if (called_back_count_ < expected_count_) {
+    waiting_ = true;
+    ui_test_utils::RunMessageLoop();
+    waiting_ = false;
+  }
+}
+
+void DownloadTestItemCreationObserver::DownloadItemCreationCallback(
+    content::DownloadId download_id, net::Error error) {
+  if (called_back_count_ >= creation_info_.size())
+    creation_info_.resize(creation_info_.size() + 1);
+  creation_info_[called_back_count_].download_id = download_id;
+  creation_info_[called_back_count_].error = error;
+  ++called_back_count_;
+
+  if (waiting_ && (called_back_count_ >= expected_count_))
+    MessageLoopForUI::current()->Quit();
+}