content sharing cannot work in scopes

[Zhang Enwei]

I tried to share one picture according to instructions in https://developer.ubuntu.com/api/scopes/cpp/sdk-15.04.1/previewwidgets/ in my scope,
Code is as below:
        PreviewWidget w_art("artId", "image");
        w_art.add_attribute_mapping("source", "art");
        w_art.add_attribute_value("zoomable", us::Variant(true));
        VariantMap share_data;
        share_data["uri"] = result()["art"];
        qDebug() << "arturi:" << QString::fromStdString(result()["art"].get_string());
        share_data["content-type"] = Variant("pictures");
        w_art.add_attribute_value("share-data", us::Variant(share_data));
        widgets.emplace_back(w_art);
I check the uri is correct.
When I tried to share the image, the Content Hub gives me some options and when I choose facebook, twitter or message, the image cannot be sent to them.
system info:
current build number: 431
device name: mako
channel: ubuntu-touch/rc-proposed/bq-aquaris.en-proposed
last update: 2016-02-03 14:41:40
version version: 431
version ubuntu: 20160203
version device: 20160112
version custom: 20160201-5-vivid

[Launchpad Janitor (janitor)]

This bug was fixed in the package unity8 - 8.11+16.04.20160310.4-0ubuntu1

---------------
unity8 (8.11+16.04.20160310.4-0ubuntu1) xenial; urgency=medium

  [ Albert Astals Cid ]
  * Add context for Re-dock as asked by translators (LP: #1534608)
  * Add emblem to the preview header widget (LP: #1424720)
  * Add haptics to ScopesListCategoryItem buttons
  * Audio Cards: Make some of the image loading async (LP: #1533432)
  * Do not create fallback code for the card tool fake card (LP:
    #1545865)
  * Fix resizing the dash bringing temp scopes size out of sync (LP:
    #1543130)
  * Minor fixes for unity-scope-tool
  * Resolve title alignment on card creator time instead of on runtime
  * Use fixedHeaderHeight only in the non cardtool cards
  * Use the new undeprecated connectivityqt::Connectivity
  * asynchronous is only false on the fake card in cardtool
  * clazy fixes

  [ Albert Astals Cid, CI Train Bot ]
  * click scope: Add the else branch so we reset the card size in all
    situations

  [ Andrea Cimitan ]
  * PreviewSharing widget now accepts both string and array of
    widgetData["share-data"]["uri"] (LP: #1549056)
  * Update AP tests for new single preview
  * Use Text.Wrap for body notification text (LP: #1544909)

  [ Andrea Cimitan, Lukáš Tinkl, Michael Zanetti, Nick Dedekind ]
  * some fixes for the new palette (LP: #1554616)

  [ CI Train Bot ]
  * Resync trunk.
  * Update translation template

  [ CI Train Bot, Daniel d'Andrada ]
  * Ensure the QML engine doesn't delete our mock MirSurfaces on its
    own.

  [ Daniel d'Andrada ]
  * tst_Shell: Remove unused qml items

  [ Josh Arenson ]
  * Allow the shell to blacklist input devices and force the OSK shown.
    (LP: #1542224)

  [ Lukáš Tinkl ]
  * Disallow resizing windows up, past the Panel (LP: #1544766)
  * Elide the window title not to let it overflow into the indicators
    area (LP: #1535767)
  * Enable the PIN lockscreen to be used with a HW keyboard (LP:
    #1550359)
  * Fix tiny windows when switching stages
  * Provide a range of ports to QML JS Debugger
  * Watch for launcher item icon changes (LP: #1543290)

  [ Michael Terry ]
  * Proxy more mouse and touchpad properties to USC (LP: #1540398) (LP:
    #1543344, #1540398)
  * Refactor the AccountsService plugin and make it slightly faster.
  * To let the user log in if a mouse is connected, hide the greeter
    cover page on a mouse click (but NOT a touch click). (LP: #1540497)
  * Watch AccountsService for changes to the user's real name. This was
    preventing us from noticing when the user set their name in the
    welcome wizard.

  [ Michael Zanetti ]
  * Allow alt+tabbing in staged mode too (LP: #1540502)
  * Allow invoking the staged mode spreads by mouse right edge pushes
    too (LP: #1540392)
  * Allow loading the device configuration from an external file
  * Implement Launcher's keyboard navigation and updated pip design
  * Make launcher scalable, allow it locking (LP: #1511015)
  * Properly parent launcher items in all cases (LP: #1495732)
  * Read inputMethod surface from the new property int QtMir (LP:
    #1545286)
  * Some visual updates and rotation lock for the virtual touchpad (LP:
    ...