Merge changes I97efd6c9,I6460f8f0,Ic67e4290,I16214514,Ieaa4e463, ... into nyc-dev am: 6cfb89c0

am: 094848e9

* commit '094848e9':
  vulkan: remove g_device_layers
  vulkan: ignore device-only layers
  vulkan: ignore layer libraries without instance layers
  vulkan: add FindLayer helper
  vulkan: constify LayerRef members
  vulkan: make g_library_mutex per-LayerLibrary
  vulkan: make LayerLibrary a class
  vulkan: refactor GetLayerGetProcAddr
  vulkan: refactor AddLayerLibrary
  vulkan: refactor LayerRef::~LayerRef
  vulkan: refactor GetLayerRef
  vulkan: add a constructor for LayerLibrary

Change-Id: Ib81d31fe67ac270d35050aa8b0e7db57ddd6324e