Android NDK package: add filegroup for Vulkan validation layers

[hevrard]

Description of the feature request:

Provide a mean to access Vulkan validation layers which are precompiled dynamic libraries shipped in Android NDK.

Android NDK BUILD file is generated by Bazel itself (@androidndk), and offers predefined rules/target related to the NDK. Currently, I cannot find an easy way to refer to the Vulkan validation layers. These layers are shipped in:

$ANDROID_NDK_HOME/sources/third_party/vulkan/src/build-android/jniLibs/<ABI>/libVkLayer_*.so

Where ABI is arm64-v8a, x86, etc.

Feature requests: what underlying problem are you trying to solve with this feature?

Easily add Vulkan validation layers to Android app.

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

Try to refer to the Vulkan validation layers using Bazel. I think that currently you need a repository rule that can access ANDROID_NDK_HOME environment variable, and search for those layers yourself.

Have you found anything relevant by searching the web?

Nothing relevant shows up.

[jin]

//src/test/java/com/google/devtools/build/lib/bazel:bazel-rules-tests is failing. Please take a look at that. It's probably because the mocked NDK doesn't have these files..?