[Android] Fix a bug in download manager that spinner shows forever

If the backend initializes synchronously, the loading view will call
hideLoadingUi() and then showLoadingUi(), which makes the loading view
always visible.

BUG=641262

Review-Url: https://codereview.chromium.org/2294073002
Cr-Commit-Position: refs/heads/master@{#415445}

chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadManagerUi.java

@@ -148,16 +148,15 @@ public class DownloadManagerUi implements OnMenuItemClickListener {
 
         mMainView = (ViewGroup) LayoutInflater.from(activity).inflate(R.layout.download_main, null);
 
-        mHistoryAdapter = new DownloadHistoryAdapter(isOffTheRecord, parentComponent);
-        mHistoryAdapter.initialize(mBackendProvider);
-        addObserver(mHistoryAdapter);
-        mHistoryAdapter.registerAdapterDataObserver(mAdapterObserver);
-
         mEmptyView = mMainView.findViewById(R.id.empty_view);
-
         mLoadingView = (LoadingView) mMainView.findViewById(R.id.loading_view);
         mLoadingView.showLoadingUI();
 
+        mHistoryAdapter = new DownloadHistoryAdapter(isOffTheRecord, parentComponent);
+        mHistoryAdapter.registerAdapterDataObserver(mAdapterObserver);
+        mHistoryAdapter.initialize(mBackendProvider);
+        addObserver(mHistoryAdapter);
+
         mSpaceDisplay = new SpaceDisplay(mMainView, mHistoryAdapter);
         mHistoryAdapter.registerAdapterDataObserver(mSpaceDisplay);
         mSpaceDisplay.onChanged();