[ermine] Launch Ask bar on long press.

Also dismiss Ask bar when on top of story.

Change-Id: I6c8fa99646c4ef45b9abfb5212796fd6b9ad070b
diff --git a/shell/ermine/lib/src/widgets/app.dart b/shell/ermine/lib/src/widgets/app.dart
index a3e4f7f..c0ace9a 100644
--- a/shell/ermine/lib/src/widgets/app.dart
+++ b/shell/ermine/lib/src/widgets/app.dart
@@ -33,30 +33,38 @@
                   children: <Widget>[
                     // Stories.
                     Positioned.fill(
-                      child: Stories(
-                        elevation: 10.0,
-                        storyManager: model.storyManager,
-                        onChangeStory: (i) {
-                          if (i == 0) {
-                            model.onMeta();
-                          }
-                        },
+                      child: GestureDetector(
+                        behavior: HitTestBehavior.translucent,
+                        child: Stories(
+                          elevation: 10.0,
+                          storyManager: model.storyManager,
+                          onChangeStory: (i) {
+                            if (i == 0) {
+                              model.onMeta();
+                            }
+                          },
+                        ),
+                        onLongPress: model.onMeta,
                       ),
                     ),
                     // Ask.
                     Positioned.fill(
-                      child: AnimatedBuilder(
-                        animation: Listenable.merge([
-                          model.askVisibility,
-                          model.askChildViewConnection
-                        ]),
-                        builder: (context, child) => Offstage(
-                              offstage: !model.askVisibility.value ||
-                                  model.askChildViewConnection.value == null,
-                              child: ChildView(
-                                connection: model.askChildViewConnection.value,
+                      child: GestureDetector(
+                        onTap: model.onCancel,
+                        child: AnimatedBuilder(
+                          animation: Listenable.merge([
+                            model.askVisibility,
+                            model.askChildViewConnection
+                          ]),
+                          builder: (context, child) => Offstage(
+                                offstage: !model.askVisibility.value ||
+                                    model.askChildViewConnection.value == null,
+                                child: ChildView(
+                                  connection:
+                                      model.askChildViewConnection.value,
+                                ),
                               ),
-                            ),
+                        ),
                       ),
                     ),
                   ],