fixed Metal release build

Bug: skia:
Change-Id: Iedb7a719f8993ed516bbad6ab3aaadcd4e14b207
Reviewed-on: https://skia-review.googlesource.com/c/162160
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
diff --git a/src/gpu/mtl/GrMtlGpuCommandBuffer.h b/src/gpu/mtl/GrMtlGpuCommandBuffer.h
index db63860..9e1ce45 100644
--- a/src/gpu/mtl/GrMtlGpuCommandBuffer.h
+++ b/src/gpu/mtl/GrMtlGpuCommandBuffer.h
@@ -121,7 +121,9 @@
 
     GrMtlGpu*                                     fGpu;
     // GrRenderTargetProxy bounds
+#ifdef SK_DEBUG
     SkRect                                        fBounds;
+#endif
     GrGpuRTCommandBuffer::LoadAndStoreInfo        fColorLoadAndStoreInfo;
     GrGpuRTCommandBuffer::StencilLoadAndStoreInfo fStencilLoadAndStoreInfo;
 
diff --git a/src/gpu/mtl/GrMtlGpuCommandBuffer.mm b/src/gpu/mtl/GrMtlGpuCommandBuffer.mm
index 9864690..72e5c2e 100644
--- a/src/gpu/mtl/GrMtlGpuCommandBuffer.mm
+++ b/src/gpu/mtl/GrMtlGpuCommandBuffer.mm
@@ -20,7 +20,9 @@
         const GrGpuRTCommandBuffer::StencilLoadAndStoreInfo& stencilInfo)
         : INHERITED(rt, origin)
         , fGpu(gpu)
+#ifdef SK_DEBUG
         , fBounds(bounds)
+#endif
         , fColorLoadAndStoreInfo(colorInfo)
         , fStencilLoadAndStoreInfo(stencilInfo)
         , fRenderPassDesc(this->createRenderPassDesc()) {