Bubble bar drop targets have been added to the TaskbarDragController
used in the TaskbarOverlayContext. This enables dragging taskbar icons
to the bubble bar drop zone from the search view on the overview screen.
Bug: 399678274
Flag: com.android.wm.shell.enable_create_any_bubble
Test: Manual. Go to the overview screen. Click the search icon. Drag any
application icon from the grid to the bubble bar drop zone. Drop the
application icon.
Change-Id: I33eb13785d8837fefc717a95a6566d3091ec855b
mpodolian
61de3b43cb