Support Noop Copy for B2T, T2B and T2T Copies

In B2T, T2B and T2T copies, copySize has 0 in width, height or depth
will trigger errors in D3D12 backend.

This patch bypass the command record step for noop copy. But all
validation rules still applies to the copy.

BUG=dawn:255

Change-Id: I4d01cef2e3c1f78440014c2c6ac63a48310d99af
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/28521
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>

src/utils/TestUtils.cpp

@@ -87,6 +87,14 @@ namespace utils {
         }
     }
 
+    uint64_t GetTexelCountInCopyRegion(uint64_t bytesPerRow,
+                                       uint64_t rowsPerImage,
+                                       wgpu::Extent3D copyExtent,
+                                       wgpu::TextureFormat textureFormat) {
+        return RequiredBytesInCopy(bytesPerRow, rowsPerImage, copyExtent, textureFormat) /
+               utils::GetTexelBlockSizeInBytes(textureFormat);
+    }
+
     void UnalignDynamicUploader(wgpu::Device device) {
         std::vector<uint8_t> data = {1};
 

src/utils/TestUtils.h

@@ -46,6 +46,11 @@ namespace utils {
                                  wgpu::Extent3D copyExtent,
                                  wgpu::TextureFormat textureFormat);
 
+    uint64_t GetTexelCountInCopyRegion(uint64_t bytesPerRow,
+                                       uint64_t rowsPerImage,
+                                       wgpu::Extent3D copyExtent,
+                                       wgpu::TextureFormat textureFormat);
+
     // A helper function used for testing DynamicUploader offset alignment.
     // A call of this function will do a Queue::WriteTexture with 1 byte of data,
     // so that assuming that WriteTexture uses DynamicUploader, the first RingBuffer