Create new buffer (if necessary) on vkMap

src/gpu/vk/GrVkBuffer.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 "GrVkBuffer.h"
 #include "GrVkGpu.h"
 #include "GrVkMemory.h"
@@ skipping 107 matching lines @@
 void GrVkBuffer::vkAbandon() {
     fResource->unrefAndAbandon();
     fMapPtr = nullptr;
     VALIDATE();
 }
 
 void* GrVkBuffer::vkMap(const GrVkGpu* gpu) {
     VALIDATE();
     SkASSERT(!this->vkIsMapped());
 
-    // we should be the only owner
-    SkASSERT(fResource->unique());
+    if (!fResource->unique()) {
+        // in use by the command buffer, so we need to create a new one
+        fResource->unref(gpu);
+        fResource = Create(gpu, fDesc);
+    }
 
     VkResult err = VK_CALL(gpu, MapMemory(gpu->device(), alloc(), 0, VK_WHOLE_SIZE, 0, &fMapPtr));
     if (err) {
         fMapPtr = nullptr;
     }
 
     VALIDATE();
     return fMapPtr;
 }
 
@@ skipping 37 matching lines @@
 
     return true;
 }
 
 void GrVkBuffer::validate() const {
     SkASSERT(!fResource || kVertex_Type == fDesc.fType || kIndex_Type == fDesc.fType
              || kCopyRead_Type == fDesc.fType || kCopyWrite_Type == fDesc.fType
              || kUniform_Type == fDesc.fType);
 }