Fixed focus transfer for GridLayoutManager and Leanback picker widgets

GridLayoutManager continued focus search even if the parent blocked the
focus delivery to its children. Also, Picker widget did not have the
right focus logic for the containing view and its child text views in
activated/deactivated modes. This CL fixed these 2 issues.

Bug: 34814581
Test: ./gradlew support-leanback-v17:connectedCheck
-Pandroid.testInstrumentationRunnerArguments.class=android.support.v17.leanback.widget.DatePickerTest
./gradlew support-leanback-v17:connectedCheck
-Pandroid.testInstrumentationRunnerArguments.class=android.support.v17.leanback.app.wizard.GuidedDatePickerTest

Change-Id: I90d4b9f870ae3f16c4591fd0b1e085a568ca4c7d
8 files changed