Add MtlTexture class.

Bug: skia:12466
Change-Id: I6207af8bb34ccab28265ced733e1930f42e2db8b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/454776
Reviewed-by: Robert Phillips <robertphillips@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>

experimental/graphite/src/mtl/MtlTexture.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef skgpu_MtlTexture_DEFINED
+#define skgpu_MtlTexture_DEFINED
+
+#include "experimental/graphite/src/Texture.h"
+
+namespace skgpu::mtl {
+
+class Texture : public skgpu::Texture {
+public:
+    static sk_sp<Texture> Make(SkISize dimensions);
+
+    ~Texture() override {}
+
+private:
+    Texture(SkISize dimensions, const skgpu::TextureInfo& info)
+            : skgpu::Texture(dimensions, info) {}
+};
+
+} // namepsace skgpu::mtl
+
+#endif // skgpu_MtlTexture_DEFINED

experimental/graphite/src/mtl/MtlTexture.mm

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "experimental/graphite/src/mtl/MtlTexture.h"
+
+#include "experimental/graphite/include/mtl/MtlTypes.h"
+
+#import <Metal/Metal.h>
+
+namespace skgpu::mtl {
+
+sk_sp<Texture> Texture::Make(SkISize dimensions) {
+    TextureInfo mtlInfo;
+    mtlInfo.fSampleCount = 1;
+    mtlInfo.fLevelCount = 1;
+
+    mtlInfo.fFormat = MTLPixelFormatRGBA8Unorm;
+    if (@available(macOS 10.11, ios 9.0, *)) {
+        mtlInfo.fUsage = MTLTextureUsageShaderRead | MTLTextureUsageRenderTarget;
+        mtlInfo.fStorageMode = MTLStorageModePrivate;
+    }
+
+    skgpu::TextureInfo textureInfo(mtlInfo);
+
+    return sk_sp<Texture>(new Texture(dimensions, textureInfo));
+}
+
+} // namespace skgpu::mtl
+

gn/graphite.gni

@@ -64,6 +64,8 @@ skia_graphite_mtl_sources = [
   "$_src/mtl/MtlPipeline.mm",
   "$_src/mtl/MtlResourceProvider.h",
   "$_src/mtl/MtlResourceProvider.mm",
+  "$_src/mtl/MtlTexture.h",
+  "$_src/mtl/MtlTexture.mm",
   "$_src/mtl/MtlTrampoline.h",
   "$_src/mtl/MtlTrampoline.mm",
   "$_src/mtl/MtlTypesPriv.mm",