Defaulting all downloads to go through Chrome network stack

chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.download;
 
 import android.app.Activity;
 import android.app.DownloadManager;
 import android.content.ActivityNotFoundException;
 import android.content.BroadcastReceiver;
@@ skipping 16 matching lines @@
 import org.chromium.base.ContextUtils;
 import org.chromium.base.Log;
 import org.chromium.base.ObserverList;
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.SuppressFBWarnings;
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeActivity;
-import org.chromium.chrome.browser.ChromeFeatureList;
 import org.chromium.chrome.browser.download.ui.BackendProvider;
 import org.chromium.chrome.browser.download.ui.DownloadHistoryAdapter;
 import org.chromium.chrome.browser.externalnav.ExternalNavigationDelegateImpl;
 import org.chromium.net.ConnectionType;
 import org.chromium.net.NetworkChangeNotifierAutoDetect;
 import org.chromium.net.RegistrationPolicyAlwaysRegister;
 import org.chromium.ui.widget.Toast;
 
 import java.io.File;
 import java.util.ArrayList;
@@ skipping 1008 matching lines @@
     protected void setDownloadSnackbarController(
             DownloadSnackbarController downloadSnackbarController) {
         mDownloadSnackbarController = downloadSnackbarController;
     }
 
     /**
      * Open the Activity which shows a list of all downloads.
      * @param context Application context
      */
     protected static void openDownloadsPage(Context context) {
-        if (!ChromeFeatureList.isEnabled(ChromeFeatureList.SYSTEM_DOWNLOAD_MANAGER)) {
-            // Try to open Download Home.
-            Activity lastActivity = ApplicationStatus.getLastTrackedFocusedActivity();
-            if (lastActivity instanceof ChromeActivity) {
-                int state = ApplicationStatus.getStateForActivity(lastActivity);
-                if (state >= ActivityState.CREATED && state <= ActivityState.RESUMED) {
-                    ChromeActivity chromeActivity = (ChromeActivity) lastActivity;
-                    DownloadUtils.showDownloadManager(
-                            lastActivity, chromeActivity.getActivityTab());
-                    return;
-                }
+        // Try to open Download Home.
+        Activity lastActivity = ApplicationStatus.getLastTrackedFocusedActivity();
+        if (lastActivity instanceof ChromeActivity) {
+            int state = ApplicationStatus.getStateForActivity(lastActivity);
+            if (state >= ActivityState.CREATED && state <= ActivityState.RESUMED) {
+                ChromeActivity chromeActivity = (ChromeActivity) lastActivity;
+                DownloadUtils.showDownloadManager(
+                        lastActivity, chromeActivity.getActivityTab());
+                return;
             }
         }
 
         // Open the Android Download Manager.

[asanka, 2016/09/19 19:29:12]

Why try to open this at all once Chrome is handling all the downloads?

Why is the behavior of openDownloadsPage() sensitive to whether the Chrome
activity is in the foreground or not?

[gone, 2016/09/19 19:33:56]

Download Home is tied to a tab: on tablets it's displayed inside a tab and in
general the downloads displayed are keyed on whether the current tab is
incognito (though I guess that's changing soon).  When Clank isn't open, it
probably makes sense to open a new tab in the browser and then send the user
into downloads, though that's clearly not how this is set up currently.

[asanka, 2016/09/19 20:05:06]

Right. Though on phones downloads home is a separate activity, correct?

I was wondering more about the fact that this code will open the downloads home
or the Android Download Manager depending on which app is in the foreground.
That seems incorrect when Chrome is handling all downloads since the in-progress
download that triggered the openDownloadsPage call won't be in the ADM.

[gone, 2016/09/19 20:10:42]

Separate activity, but it's still tied to whether the tab was incognito or not. 
This shouldn't matter once the manager is showing all regular and incognito
downloads in the same list regardless of how it was opened.  As a fallback, we
could change DownloadUtils#showDownloadManager() to pop up Download Home without
any idea of what Chrome's state is.  It already handles null tabs, but it'd need
to be adjusted to account for null activities, as well.

The logic requires some tweaking there, though.  If you file a bug I can try to
tweak it to make more sense.

[qinmin, 2016/09/19 21:16:13]

For OMA downloads, which didn't go through Chrome, we need to open it in Android
DownloadManager

         Intent pageView = new Intent(DownloadManager.ACTION_VIEW_DOWNLOADS);
         pageView.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
         try {
             context.startActivity(pageView);
         } catch (ActivityNotFoundException e) {
             Log.e(TAG, "Cannot find Downloads app", e);
         }
     }
 
     /**
@@ skipping 566 matching lines @@
             boolean isNotificationDismissed);
     private native void nativePauseDownload(long nativeDownloadManagerService, String downloadGuid,
             boolean isOffTheRecord);
     private native void nativeRemoveDownload(long nativeDownloadManagerService, String downloadGuid,
             boolean isOffTheRecord);
     private native void nativeGetAllDownloads(
             long nativeDownloadManagerService, boolean isOffTheRecord);
     private native void nativeCheckForExternallyRemovedDownloads(
             long nativeDownloadManagerService, boolean isOffTheRecord);
 }