message: Partially fix ComputeCopyStorageBufferTests.DISABLED_UnsizedArray
  And update test names + comments on several ComputeCopyStorageBufferTests cases.
diff: @@ -91,7 +91,7 @@ void ComputeCopyStorageBufferTests::BasicTest(const char* shader) {
  }
  // Test that a trivial compute-shader memcpy implementation works.
  -TEST_P(ComputeCopyStorageBufferTests, BasicTest) {
  +TEST_P(ComputeCopyStorageBufferTests, SizedArrayOfBasic) {
  BasicTest(R"(
  #version 450
  #define kInstances 4
  @@ -105,7 +105,9 @@ TEST_P(ComputeCopyStorageBufferTests, BasicTest) {
  }
  // Test that a slightly-less-trivial compute-shader memcpy implementation works.
  -TEST_P(ComputeCopyStorageBufferTests, StructTest) {
  +//
  +// TODO(kainino@chromium.org): Fails on D3D12 backend. Probably due to a limitation in SPIRV-Cross?
  +TEST_P(ComputeCopyStorageBufferTests, SizedArrayOfStruct) {
  BasicTest(R"(
  #version 450
  #define kInstances 4
  @@ -121,10 +123,25 @@ TEST_P(ComputeCopyStorageBufferTests, StructTest) {
  })");
  }
  -// Test with a sized array SSBO.
  -TEST_P(ComputeCopyStorageBufferTests, DISABLED_SizedArray) {
  - // TODO(kainino@chromium.org): Fails on OpenGL (only copies one instance, not 4).
  - // TODO(kainino@chromium.org): Fails on Vulkan (program hangs).
  +// Test that a trivial compute-shader memcpy implementation works.
  +TEST_P(ComputeCopyStorageBufferTests, UnsizedArrayOfBasic) {
  + BasicTest(R"(
  + #version 450
  + #define kInstances 4
  + layout(std140, set = 0, binding = 0) buffer Src { uvec4 s[]; } src;
  + layout(std140, set = 0, binding = 1) buffer Dst { uvec4 s[]; } dst;
  + void main() {
  + uint index = gl_GlobalInvocationID.x;
  + if (index >= kInstances) { return; }
  + dst.s[index] = src.s[index];
  + })");
  +}
  +
  +// Test binding a sized array of SSBO descriptors.
  +//
  +// This is disabled because WebGPU doesn't currently have binding arrays (equivalent to
  +// VkDescriptorSetLayoutBinding::descriptorCount). https://github.com/gpuweb/gpuweb/pull/61
  +TEST_P(ComputeCopyStorageBufferTests, DISABLED_SizedDescriptorArray) {
  BasicTest(R"(
  #version 450
  #define kInstances 4
  @@ -140,12 +157,15 @@ TEST_P(ComputeCopyStorageBufferTests, DISABLED_SizedArray) {
  })");
  }
  -// Test with an unsized array SSBO.
  -TEST_P(ComputeCopyStorageBufferTests, DISABLED_UnsizedArray) {
  - // TODO(kainino@chromium.org): On OpenGL, compilation fails but the test passes. Why?
  - // TODO(kainino@chromium.org): On Metal, compilation fails and test crashes.
  +// Test binding an unsized array of SSBO descriptors.
  +//
  +// TODO(kainino@chromium.org): This test may be somewhat wrong. I'm not sure whether this is
  +// supposed to be possible on the various native APIs.
  +// Linking on OpenGL fails with "OpenGL requires constant indexes for unsized array access(dst)".
  +TEST_P(ComputeCopyStorageBufferTests, DISABLED_UnsizedDescriptorArray) {
  BasicTest(R"(
  #version 450
  + #extension GL_EXT_nonuniform_qualifier : require
  #define kInstances 4
  struct S {
  uvec2 a, b; // kUintsPerInstance = 4
  