[graphite] Add basic Texture files.

Bug: skia:12466
Change-Id: If708d8a4bd00802e60a860215edcb64db179e573
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/454616
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>

experimental/graphite/include/TextureInfo.h

@@ -16,6 +16,13 @@
 
 namespace skgpu {
 
+// Forward declares so we can friend classes in other namespaces
+#ifdef SK_METAL
+namespace mtl {
+    class Caps;
+}
+#endif
+
 class TextureInfo {
 public:
     TextureInfo() {}
@@ -44,7 +51,7 @@ public:
         if (!this->isValid() || fBackend != BackendApi::kMetal) {
             return false;
         }
-        *info = mtl::TextureSpecToTextureInfo(fMtlSpec, fSampleCount, fLevelCount, fProtected);
+        *info = mtl::TextureSpecToTextureInfo(fMtlSpec, fSampleCount, fLevelCount);
         return true;
     }
 #endif

experimental/graphite/src/Texture.cpp

@@ -0,0 +1,17 @@
+/*
+ * 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/Texture.h"
+
+namespace skgpu {
+
+Texture::Texture(SkISize dimensions, const TextureInfo& info)
+        : fDimensions(dimensions), fInfo(info) {}
+
+Texture::~Texture() {}
+
+} // namespace skgpu

experimental/graphite/src/Texture.h

@@ -0,0 +1,34 @@
+/*
+ * 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_Texture_DEFINED
+#define skgpu_Texture_DEFINED
+
+#include "experimental/graphite/include/TextureInfo.h"
+#include "include/core/SkRefCnt.h"
+#include "include/core/SkSize.h"
+
+namespace skgpu {
+
+class Texture : public SkRefCnt {
+public:
+    ~Texture() override;
+
+    SkISize dimensions() const { return fDimensions; }
+    const TextureInfo& textureInfo() const { return fInfo; }
+
+protected:
+    Texture(SkISize dimensions, const TextureInfo& info);
+
+private:
+    SkISize fDimensions;
+    TextureInfo fInfo;
+};
+
+} // namepsace skgpu
+
+#endif // skgpu_Texture_DEFINED

gn/graphite.gni

@@ -46,6 +46,8 @@ skia_graphite_sources = [
   "$_src/Surface_Graphite.h",
   "$_src/Task.cpp",
   "$_src/Task.h",
+  "$_src/Texture.cpp",
+  "$_src/Texture.h",
 ]
 
 skia_graphite_mtl_sources = [