[graphite] Add ResourceProvider to Gpu

Bug: skia:12466
Change-Id: I1224ad193bb9d866439673161075e29adedc0008
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/456475
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>

experimental/graphite/src/Gpu.h

@@ -30,10 +30,10 @@ public:
 protected:
     Gpu(sk_sp<const Caps>);
 
+    std::unique_ptr<ResourceProvider> fResourceProvider;
+
 private:
     sk_sp<const Caps> fCaps;
-
-    std::unique_ptr<ResourceProvider> fResourceProvider;
 };
 
 } // namespace skgpu

experimental/graphite/src/mtl/MtlGpu.mm

@@ -8,6 +8,7 @@
 #include "experimental/graphite/src/mtl/MtlGpu.h"
 
 #include "experimental/graphite/src/Caps.h"
+#include "experimental/graphite/src/mtl/MtlResourceProvider.h"
 
 namespace skgpu::mtl {
 
@@ -24,6 +25,7 @@ Gpu::Gpu(sk_cfp<id<MTLDevice>> device, sk_cfp<id<MTLCommandQueue>> queue, sk_sp<
     : skgpu::Gpu(std::move(caps))
     , fDevice(std::move(device))
     , fQueue(std::move(queue)) {
+    fResourceProvider.reset(new ResourceProvider(this));
 }
 
 Gpu::~Gpu() {