Add vulkan files into skia repo. This is an incomplete backend with only partial functionality at this time.

R=robertphillips@google.com
TBR=bsalomon@google.com

BUG=skia:4955
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1718693002

Committed: https://skia.googlesource.com/skia/+/48cf268defad66f58f1aa03b4835e5583be96b2f

Review URL: https://codereview.chromium.org/1718693002
diff --git a/src/gpu/vk/GrVkTextureRenderTarget.h b/src/gpu/vk/GrVkTextureRenderTarget.h
new file mode 100644
index 0000000..6e0d899
--- /dev/null
+++ b/src/gpu/vk/GrVkTextureRenderTarget.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+#ifndef GrVkTextureRenderTarget_DEFINED
+#define GrVkTextureRenderTarget_DEFINED
+
+#include "GrVkTexture.h"
+#include "GrVkRenderTarget.h"
+#include "GrVkGpu.h"
+
+#ifdef SK_BUILD_FOR_WIN
+// Windows gives bogus warnings about inheriting asTexture/asRenderTarget via dominance.
+#pragma warning(push)
+#pragma warning(disable: 4250)
+#endif
+
+class GrVkImageView;
+
+class GrVkTextureRenderTarget: public GrVkTexture, public GrVkRenderTarget {
+public:
+    static GrVkTextureRenderTarget* CreateNewTextureRenderTarget(GrVkGpu*, const GrSurfaceDesc&,
+                                                                 GrGpuResource::LifeCycle,
+                                                                 const GrVkImage::ImageDesc&);
+
+    static GrVkTextureRenderTarget* CreateWrappedTextureRenderTarget(GrVkGpu*, 
+                                                                     const GrSurfaceDesc&,
+                                                                     GrGpuResource::LifeCycle,
+                                                                     VkFormat,
+                                                                     GrVkImage::Resource*);
+
+protected:
+    void onAbandon() override {
+        GrVkRenderTarget::onAbandon();
+        GrVkTexture::onAbandon();
+    }
+
+    void onRelease() override {
+        GrVkRenderTarget::onRelease();
+        GrVkTexture::onRelease();
+    }
+
+private:
+    GrVkTextureRenderTarget(GrVkGpu* gpu,
+                            const GrSurfaceDesc& desc,
+                            GrGpuResource::LifeCycle lifeCycle,
+                            const GrVkImage::Resource* imageResource,
+                            const GrVkImageView* texView,
+                            const GrVkImage::Resource* msaaResource,
+                            const GrVkImageView* colorAttachmentView,
+                            const GrVkImageView* resolveAttachmentView)
+        : GrSurface(gpu, lifeCycle, desc)
+        , GrVkImage(imageResource)
+        , GrVkTexture(gpu, desc, lifeCycle, imageResource, texView, GrVkTexture::kDerived)
+        , GrVkRenderTarget(gpu, desc, lifeCycle, imageResource, msaaResource, colorAttachmentView,
+                           resolveAttachmentView, GrVkRenderTarget::kDerived) {
+        this->registerWithCache();
+    }
+
+    GrVkTextureRenderTarget(GrVkGpu* gpu,
+                            const GrSurfaceDesc& desc,
+                            GrGpuResource::LifeCycle lifeCycle,
+                            const GrVkImage::Resource* imageResource,
+                            const GrVkImageView* texView,
+                            const GrVkImageView* colorAttachmentView)
+        : GrSurface(gpu, lifeCycle, desc)
+        , GrVkImage(imageResource)
+        , GrVkTexture(gpu, desc, lifeCycle, imageResource, texView, GrVkTexture::kDerived)
+        , GrVkRenderTarget(gpu, desc, lifeCycle, imageResource, colorAttachmentView,
+                           GrVkRenderTarget::kDerived) {
+        this->registerWithCache();
+    }
+
+    static GrVkTextureRenderTarget* Create(GrVkGpu*, const GrSurfaceDesc&,
+                                           GrGpuResource::LifeCycle,
+                                           VkFormat format,
+                                           const GrVkImage::Resource* imageResource);
+
+    // GrGLRenderTarget accounts for the texture's memory and any MSAA renderbuffer's memory.
+    size_t onGpuMemorySize() const override {
+        return GrVkRenderTarget::onGpuMemorySize();
+    }
+};
+
+#endif