Set depth clear value to 0 if it is unused (load op load)

VVL complains if it is NaN (the default value)

Fixed: dawn:1718
Include-Ci-Only-Tests: true
Change-Id: I397ad15dc7d5c142d7bd29f4301de27331aa7141
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/124820
Kokoro: Austin Eng <enga@chromium.org>
Commit-Queue: Austin Eng <enga@chromium.org>
Reviewed-by: Shrek Shao <shrekshao@google.com>

src/dawn/native/CommandEncoder.cpp

@@ -890,8 +890,18 @@ Ref<RenderPassEncoder> CommandEncoder::BeginRenderPass(const RenderPassDescripto
 
                 cmd->depthStencilAttachment.view = view;
 
-                cmd->depthStencilAttachment.clearDepth =
+                switch (descriptor->depthStencilAttachment->depthLoadOp) {
-                    descriptor->depthStencilAttachment->depthClearValue;
+                    case wgpu::LoadOp::Clear:
+                        cmd->depthStencilAttachment.clearDepth =
+                            descriptor->depthStencilAttachment->depthClearValue;
+                        break;
+                    case wgpu::LoadOp::Load:
+                    case wgpu::LoadOp::Undefined:
+                        // Set depthClearValue to 0 if it is the load op is not clear.
+                        // The default value NaN may be invalid in the backend.
+                        cmd->depthStencilAttachment.clearDepth = 0.f;
+                        break;
+                }
                 cmd->depthStencilAttachment.clearStencil =
                     descriptor->depthStencilAttachment->stencilClearValue;