Fix 3366514 (again): browser emulator crash

Added TilesManager::hardwareAccelerationEnabled() to check internal
gInstance without the side-effect of creating it, if null. Used by
BaseLayerAndroid to avoid creating an instance during a destructor.

Emulator will have a null gInstance, so this provides a runtime
solution that distinguishes the emulator from the device.

Change-Id: I023849d0bb405deef588d7fc272f0e303577fddf
2 files changed