First implementation of GrDawnTexture.

Change-Id: I9c636c939dffbb0b395f3e9ed3d9a55784a6d390
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/233981
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
diff --git a/src/gpu/dawn/GrDawnUtil.cpp b/src/gpu/dawn/GrDawnUtil.cpp
index ad790ba..7d9df0d 100644
--- a/src/gpu/dawn/GrDawnUtil.cpp
+++ b/src/gpu/dawn/GrDawnUtil.cpp
@@ -47,6 +47,11 @@
     }
 }
 
+size_t GrDawnRoundRowBytes(size_t rowBytes) {
+    // Dawn requires that rowBytes be a multiple of 256. (This is actually imposed by D3D12.)
+    return (rowBytes + 0xFF) & ~0xFF;
+}
+
 #if GR_TEST_UTILS
 const char* GrDawnFormatToStr(dawn::TextureFormat format) {
     switch (format) {