Fix vulkan clears

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 "GrMesh.h"
@@ skipping 171 matching lines @@
 
 void GrVkGpuCommandBuffer::onClear(GrRenderTarget* target, const SkIRect& rect, GrColor color) {
     // parent class should never let us get here with no RT
     SkASSERT(target);
 
     VkClearColorValue vkColor;
     GrColorToRGBAFloat(color, vkColor.float32);
 
     GrVkRenderTarget* vkRT = static_cast<GrVkRenderTarget*>(target);
 
-    if (fIsEmpty) {
+    if (fIsEmpty && rect.width() == target->width() && rect.height() == target->height()) {
         // We will change the render pass to do a clear load instead
         GrVkRenderPass::LoadStoreOps vkColorOps(VK_ATTACHMENT_LOAD_OP_CLEAR,
                                                 VK_ATTACHMENT_STORE_OP_STORE);
         GrVkRenderPass::LoadStoreOps vkStencilOps(VK_ATTACHMENT_LOAD_OP_LOAD,
                                                   VK_ATTACHMENT_STORE_OP_STORE);
         GrVkRenderPass::LoadStoreOps vkResolveOps(VK_ATTACHMENT_LOAD_OP_LOAD,
                                                   VK_ATTACHMENT_STORE_OP_STORE);
 
         const GrVkRenderPass* oldRP = fRenderPass;
 
@@ skipping 185 matching lines @@
             fGpu->stats()->incNumDraws();
         } while ((nonIdxMesh = iter.next()));
     }
 
     // Technically we don't have to call this here (since there is a safety check in
     // pipelineState:setData but this will allow for quicker freeing of resources if the
     // pipelineState sits in a cache for a while.
     pipelineState->freeTempResources(fGpu);
 }