Vulkan: Add Features class.

This class will control optional features in the Vulkan back-end. It
allows toggling the feature support from a centralized place. This can
be useful for performance or correctness testing.

Add a placeholder feature for line segment raster. We can also use a
feature for enabling backbuffer flipping.

Bug: angleproject:2598
Bug: angleproject:2673
Change-Id: I8ddec2dba2181d5b014267be68aee9d2cb015ccf
Reviewed-on: https://chromium-review.googlesource.com/1120149
Reviewed-by: Luc Ferron <lucferron@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/renderer/vulkan/RendererVk.cpp b/src/libANGLE/renderer/vulkan/RendererVk.cpp
index df57146..b112652 100644
--- a/src/libANGLE/renderer/vulkan/RendererVk.cpp
+++ b/src/libANGLE/renderer/vulkan/RendererVk.cpp
@@ -603,7 +603,7 @@
     if (!mCapsInitialized)
     {
         vk::GenerateCaps(mPhysicalDeviceProperties, mNativeTextureCaps, &mNativeCaps,
-                         &mNativeExtensions, &mNativeLimitations);
+                         &mNativeExtensions, &mNativeLimitations, &mFeatures);
         mCapsInitialized = true;
     }
 }