Vulkan: Support extension "depth_clamp"

This patch implements the extension "depth_clamp" on Vulkan, which
we need to test if we can correctly record "PrimitiveDepthClampingState"
in FlatRenderPipelineDescriptor - Currently FlatRenderPipelineDescriptor
fails to record this because we incorrectly ignore all the members in
"nextInChain".

BUG=dawn:529, dawn:716
TEST=dawn_end2end_tests

Change-Id: Iec407245a3f37d10a3d1428b0612f0e18e80c616
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/63820
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Jiawei Shao <jiawei.shao@intel.com>

src/dawn_native/vulkan/AdapterVk.cpp

@@ -278,6 +278,10 @@ namespace dawn_native { namespace vulkan {
             mSupportedExtensions.EnableExtension(Extension::PipelineStatisticsQuery);
         }
 
+        if (mDeviceInfo.features.depthClamp == VK_TRUE) {
+            mSupportedExtensions.EnableExtension(Extension::DepthClamping);
+        }
+
         if (mDeviceInfo.properties.limits.timestampComputeAndGraphics == VK_TRUE) {
             mSupportedExtensions.EnableExtension(Extension::TimestampQuery);
         }

src/dawn_native/vulkan/DeviceVk.cpp

@@ -387,6 +387,11 @@ namespace dawn_native { namespace vulkan {
                               VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES);
         }
 
+        if (IsExtensionEnabled(Extension::DepthClamping)) {
+            ASSERT(ToBackend(GetAdapter())->GetDeviceInfo().features.depthClamp == VK_TRUE);
+            usedKnobs.features.depthClamp = VK_TRUE;
+        }
+
         // Find a universal queue family
         {
             // Note that GRAPHICS and COMPUTE imply TRANSFER so we don't need to check for it.

src/dawn_native/vulkan/RenderPipelineVk.cpp

@@ -395,7 +395,7 @@ namespace dawn_native { namespace vulkan {
         rasterization.sType = VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO;
         rasterization.pNext = nullptr;
         rasterization.flags = 0;
-        rasterization.depthClampEnable = VK_FALSE;
+        rasterization.depthClampEnable = ShouldClampDepth() ? VK_TRUE : VK_FALSE;
         rasterization.rasterizerDiscardEnable = VK_FALSE;
         rasterization.polygonMode = VK_POLYGON_MODE_FILL;
         rasterization.cullMode = VulkanCullMode(GetCullMode());