Added support for inspector actions.

Added support for showing an document in its provider.
Added support for clearing default app to open a file.

Changed views to adhere to android materail design.
Added unit test to test if views were visible when the conditions
were met.

Cleaned up the code from prevous PTAL.

Bug: 2474141
Test: InspectorControllerTest
Change-Id: Ic4936890b34b0657ef934afe5e9bd14f5fce0f25