Optimization: remove useless layout nesting.
Optimization: remove useless layout nesting.

The entire PageFragment is surrounded by a FrameLayout that is useless.

Change-Id: I5fa6e4379aa3d6f7f85f07b04e2019932dc1e2e1

wikimedia/apps-android-wikipedia,wikimedia/apps-android-wikipedia,wikimedia/apps-android-wikipedia,dbrant/apps-android-wikipedia,dbrant/apps-android-wikipedia,dbrant/apps-android-wikipedia,wikimedia/apps-android-wikipedia,dbrant/apps-android-wikipedia,dbrant/apps-android-wikipedia