Fix compile error (uninitialized variable use)

src/gpu/vk/GrVkGpuCommandBuffer.cpp

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #include "GrVkGpuCommandBuffer.h"
 
 #include "GrVkCommandBuffer.h"
@@ skipping 22 matching lines @@
             *storeOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
             break;
         case GrGpuCommandBuffer::kDiscardAndStore_LoadAndStoreOp:
             *loadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
             *storeOp = VK_ATTACHMENT_STORE_OP_STORE;
             break;
         case GrGpuCommandBuffer::kDiscardAndDiscard_LoadAndStoreOp:
             *loadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
             *storeOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
             break;
+        default:
+            SK_ABORT("Invalid LoadAndStoreOp");
+            *loadOp = VK_ATTACHMENT_LOAD_OP_LOAD;
+            *storeOp = VK_ATTACHMENT_STORE_OP_STORE;
+            break;
     }
 }
 
 GrVkGpuCommandBuffer::GrVkGpuCommandBuffer(GrVkGpu* gpu,
                                            const GrVkRenderTarget& target,
                                            LoadAndStoreOp colorOp, GrColor colorClear,
                                            LoadAndStoreOp stencilOp, GrColor stencilClear)
     : fGpu(gpu) {
     VkAttachmentLoadOp vkLoadOp;
     VkAttachmentStoreOp vkStoreOp;
@@ skipping 30 matching lines @@
 }
 
 void GrVkGpuCommandBuffer::end() {
     fCommandBuffer->end(fGpu);
 }
 
 void GrVkGpuCommandBuffer::submit() {
     fGpu->submitSecondaryCommandBuffer(fCommandBuffer);
 }