Create and plumb SkiaBackendTexture abstraction layer over GrBackendTexture

This means AutoBackendTexture is not aware of backend-specific texture
type and API details, and will be able to accept either a Ganesh or
Graphite variant of SkiaBackendTexture.

Also delegated SkiaBackendTexture creation to SkiaGpuContext, so that
backend-specific contexts handle creating backend-specifc textures.

Test: manual validation (GL+VK) & existing tests (refactor)
Bug: b/293371537
Change-Id: Ia65306cc825b71fe0b89c7f8545ce1c71a81d86b
diff --git a/libs/renderengine/skia/compat/SkiaBackendTexture.h b/libs/renderengine/skia/compat/SkiaBackendTexture.h
new file mode 100644
index 0000000..09877a5
--- /dev/null
+++ b/libs/renderengine/skia/compat/SkiaBackendTexture.h
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <include/android/GrAHardwareBufferUtils.h>
+#include <include/core/SkColorSpace.h>
+#include <include/gpu/GrDirectContext.h>
+
+#include <android/hardware_buffer.h>
+#include <ui/GraphicTypes.h>
+
+namespace android::renderengine::skia {
+
+/**
+ * Abstraction over a Skia backend-specific texture type.
+ *
+ * This class does not do any lifecycle management, and should typically be wrapped in an
+ * AutoBackendTexture::LocalRef. Typically created via SkiaGpuContext::makeBackendTexture(...).
+ */
+class SkiaBackendTexture {
+public:
+    SkiaBackendTexture(AHardwareBuffer* buffer, bool isOutputBuffer)
+          : mIsOutputBuffer(isOutputBuffer) {
+        AHardwareBuffer_Desc desc;
+        AHardwareBuffer_describe(buffer, &desc);
+
+        mColorType = GrAHardwareBufferUtils::GetSkColorTypeFromBufferFormat(desc.format);
+    }
+    virtual ~SkiaBackendTexture() = default;
+
+    // These two definitions mirror Skia's own types used for texture release callbacks, which are
+    // re-declared multiple times between context-specific implementation headers for Ganesh vs.
+    // Graphite, and within the context of SkImages vs. SkSurfaces. Our own re-declaration allows us
+    // to not pull in any implementation-specific headers here.
+    using ReleaseContext = void*;
+    using TextureReleaseProc = void (*)(ReleaseContext);
+
+    // Guaranteed to be non-null (crashes otherwise). An opaque alphaType may coerce the internal
+    // color type to RBGX.
+    virtual sk_sp<SkImage> makeImage(SkAlphaType alphaType, ui::Dataspace dataspace,
+                                     TextureReleaseProc releaseImageProc,
+                                     ReleaseContext releaseContext) = 0;
+
+    // Guaranteed to be non-null (crashes otherwise).
+    virtual sk_sp<SkSurface> makeSurface(ui::Dataspace dataspace,
+                                         TextureReleaseProc releaseSurfaceProc,
+                                         ReleaseContext releaseContext) = 0;
+
+    bool isOutputBuffer() const { return mIsOutputBuffer; }
+
+    SkColorType internalColorType() const { return mColorType; }
+
+protected:
+    // Strip alpha channel from rawColorType if alphaType is opaque (note: only works for RGBA_8888)
+    SkColorType colorTypeForImage(SkAlphaType alphaType) const {
+        if (alphaType == kOpaque_SkAlphaType) {
+            // TODO: b/40043126 - Support RGBX SkColorType for F16 and support it and 101010x as a
+            // source
+            if (internalColorType() == kRGBA_8888_SkColorType) {
+                return kRGB_888x_SkColorType;
+            }
+        }
+        return internalColorType();
+    }
+
+private:
+    const bool mIsOutputBuffer;
+    SkColorType mColorType = kUnknown_SkColorType;
+};
+
+} // namespace android::renderengine::skia