MediaControlView2: Add support for Minimal Mode

This CL adds UX for Minimal mode.
  - Minimal mode is triggered when the minimum width required for
    Embedded mode is smaller than the current View width.
  - Create an MinimalExtraView to place FullScreen button for
    Minimal mode.

This CL also adds gradient background color for TitleBar and
implements onCallCompleted() callback to update MediaControlView2
after successfully seeking.

Bug: 74506210
Test: VideoViewTest.apk
Change-Id: I6cd35af473d0f796cd35ae8759171cc1722fc679