Add some copy support for vulkan msaa

src/gpu/vk/GrVkRenderTarget.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrVkRenderTarget.h"
 
 #include "GrRenderTargetPriv.h"
@@ skipping 117 matching lines @@
     const GrVkImageView* resolveAttachmentView = nullptr;
     if (desc.fSampleCnt) {
         GrVkImage::ImageDesc msImageDesc;
         msImageDesc.fImageType = VK_IMAGE_TYPE_2D;
         msImageDesc.fFormat = pixelFormat;
         msImageDesc.fWidth = desc.fWidth;
         msImageDesc.fHeight = desc.fHeight;
         msImageDesc.fLevels = 1;
         msImageDesc.fSamples = desc.fSampleCnt;
         msImageDesc.fImageTiling = VK_IMAGE_TILING_OPTIMAL;
-        msImageDesc.fUsageFlags = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
+        msImageDesc.fUsageFlags = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT |
+                                  VK_IMAGE_USAGE_TRANSFER_DST_BIT |
+                                  VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
         msImageDesc.fMemProps = VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT;
 
         if (!GrVkImage::InitImageInfo(gpu, msImageDesc, &msInfo)) {
             return nullptr;
         }
 
         // Set color attachment image
         colorImage = msInfo.fImage;
 
         // Create Resolve attachment view
@@ skipping 224 matching lines @@
     }
 
     return nullptr;
 }
 
 
 GrVkGpu* GrVkRenderTarget::getVkGpu() const {
     SkASSERT(!this->wasDestroyed());
     return static_cast<GrVkGpu*>(this->getGpu());
 }