Add addtional resolve calls to vulkan backend

src/gpu/vk/GrVkRenderTarget.h

 /*
  * 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 GrVkRenderTarget_DEFINED
 #define GrVkRenderTarget_DEFINED
@@ skipping 42 matching lines @@
     const GrVkResource* stencilImageResource() const;
     const GrVkImageView* stencilAttachmentView() const;
 
     const GrVkRenderPass* simpleRenderPass() const { return fCachedSimpleRenderPass; }
     GrVkResourceProvider::CompatibleRPHandle compatibleRenderPassHandle() const {
         return fCompatibleRPHandle;
     }
 
     // override of GrRenderTarget
     ResolveType getResolveType() const override {
-        return kCanResolve_ResolveType;
+        if (this->numColorSamples() > 1) {
+            return kCanResolve_ResolveType;
+        }
+        return kAutoResolves_ResolveType;
     }
 
     bool canAttemptStencilAttachment() const override {
         return true;
     }
 
     GrBackendObject getRenderTargetHandle() const override;
 
     void getAttachmentsDescriptor(GrVkRenderPass::AttachmentsDescriptor* desc,
                                   GrVkRenderPass::AttachmentFlags* flags) const;
@@ skipping 64 matching lines @@
     int                        fColorValuesPerPixel;
 
     // This is a cached pointer to a simple render pass. The render target should unref it
     // once it is done with it.
     const GrVkRenderPass*      fCachedSimpleRenderPass;
     // This is a handle to be used to quickly get compatible GrVkRenderPasses for this render target
     GrVkResourceProvider::CompatibleRPHandle fCompatibleRPHandle;
 };
 
 #endif