Have GrSurfaceProxys and GrGpuResources draw from the same pool of unique ids

The idea here is that, for wrapped Proxy objects, we want the uniqueID to reflect that of the wrapped object. For this to work the IDs for the non-wrapped versions can't conflict with GrGpuResource's pool of IDs.

Split off of: https://codereview.chromium.org/2215323003/ (Start using RenderTargetProxy (omnibus))

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2301523003

Review-Url: https://codereview.chromium.org/2301523003
diff --git a/src/gpu/batches/GrClearBatch.h b/src/gpu/batches/GrClearBatch.h
index 7d84bc3..27e19fa 100644
--- a/src/gpu/batches/GrClearBatch.h
+++ b/src/gpu/batches/GrClearBatch.h
@@ -29,7 +29,7 @@
 
     const char* name() const override { return "Clear"; }
 
-    uint32_t renderTargetUniqueID() const override { return fRenderTarget.get()->getUniqueID(); }
+    uint32_t renderTargetUniqueID() const override { return fRenderTarget.get()->uniqueID(); }
     GrRenderTarget* renderTarget() const override { return fRenderTarget.get(); }
 
     SkString dumpInfo() const override {
@@ -38,7 +38,7 @@
             const SkIRect& r = fClip.scissorRect();
             string.appendf("L: %d, T: %d, R: %d, B: %d", r.fLeft, r.fTop, r.fRight, r.fBottom);
         }
-        string.appendf("], Color: 0x%08x, RT: %d", fColor, fRenderTarget.get()->getUniqueID());
+        string.appendf("], Color: 0x%08x, RT: %d", fColor, fRenderTarget.get()->uniqueID());
         string.append(INHERITED::dumpInfo());
         return string;
     }