Add null check in ViewOverlay

View.getOverlay().clear() can failed with an NPE if there are
no drawables in the overlay. Fix: add a null check before dereferencing
the mDrawables field.

Issue #8895794 getOverlay.clear() crashes if drawables were not added previously

Change-Id: I9b2a63036450915681ba3a89a0911e2490063702
1 file changed