Fix possible divide by zero in vulkan granularity adjustments

src/gpu/vk/GrVkGpu.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 "GrVkGpu.h"
 
 #include "GrContextOptions.h"
@@ skipping 1767 matching lines @@
     transferBuffer->unref();
     return true;
 }
 
 // The RenderArea bounds we pass into BeginRenderPass must have a start x value that is a multiple
 // of the granularity. The width must also be a multiple of the granularity or eaqual to the width
 // the the entire attachment. Similar requirements for the y and height components.
 void adjust_bounds_to_granularity(SkIRect* dstBounds, const SkIRect& srcBounds,
                                   const VkExtent2D& granularity, int maxWidth, int maxHeight) {
     // Adjust Width
-    // Start with the right side of rect so we know if we end up going pass the maxWidth.
-    int rightAdj = srcBounds.fRight % granularity.width;
-    if (rightAdj != 0) {
-        rightAdj = granularity.width - rightAdj;
-    }
-    dstBounds->fRight = srcBounds.fRight + rightAdj;
-    if (dstBounds->fRight > maxWidth) {
-        dstBounds->fRight = maxWidth;
-        dstBounds->fLeft = 0;
+    if ((0 != granularity.width && 1 != granularity.width)) {
+        // Start with the right side of rect so we know if we end up going pass the maxWidth.
+        int rightAdj = srcBounds.fRight % granularity.width;
+        if (rightAdj != 0) {
+            rightAdj = granularity.width - rightAdj;
+        }
+        dstBounds->fRight = srcBounds.fRight + rightAdj;
+        if (dstBounds->fRight > maxWidth) {
+            dstBounds->fRight = maxWidth;
+            dstBounds->fLeft = 0;
+        } else {
+            dstBounds->fLeft = srcBounds.fLeft - srcBounds.fLeft % granularity.width;
+        }
     } else {
-       dstBounds->fLeft = srcBounds.fLeft - srcBounds.fLeft % granularity.width;
+        dstBounds->fLeft = srcBounds.fLeft;
+        dstBounds->fRight = srcBounds.fRight;
     }
 
     // Adjust height
-    // Start with the bottom side of rect so we know if we end up going pass the maxHeight.
-    int bottomAdj = srcBounds.fBottom % granularity.height;
-    if (bottomAdj != 0) {
-        bottomAdj = granularity.height - bottomAdj;
-    }
-    dstBounds->fBottom = srcBounds.fBottom + bottomAdj;
-    if (dstBounds->fBottom > maxHeight) {
-        dstBounds->fBottom = maxHeight;
-        dstBounds->fTop = 0;
+    if ((0 != granularity.height && 1 != granularity.height)) {
+        // Start with the bottom side of rect so we know if we end up going pass the maxHeight.
+        int bottomAdj = srcBounds.fBottom % granularity.height;
+        if (bottomAdj != 0) {
+            bottomAdj = granularity.height - bottomAdj;
+        }
+        dstBounds->fBottom = srcBounds.fBottom + bottomAdj;
+        if (dstBounds->fBottom > maxHeight) {
+            dstBounds->fBottom = maxHeight;
+            dstBounds->fTop = 0;
+        } else {
+            dstBounds->fTop = srcBounds.fTop - srcBounds.fTop % granularity.height;
+        }
     } else {
-       dstBounds->fTop = srcBounds.fTop - srcBounds.fTop % granularity.height;
+        dstBounds->fTop = srcBounds.fTop;
+        dstBounds->fBottom = srcBounds.fBottom;
     }
 }
 
 void GrVkGpu::submitSecondaryCommandBuffer(GrVkSecondaryCommandBuffer* buffer,
                                            const GrVkRenderPass* renderPass,
                                            const VkClearValue* colorClear,
                                            GrVkRenderTarget* target,
                                            const SkIRect& bounds) {
     const SkIRect* pBounds = &bounds;
     SkIRect flippedBounds;
@@ skipping 18 matching lines @@
     // Currently it is fine for us to always pass in 1 for the clear count even if no attachment
     // uses it. In the current state, we also only use the LOAD_OP_CLEAR for the color attachment
     // which is always at the first attachment.
     fCurrentCmdBuffer->beginRenderPass(this, renderPass, 1, colorClear, *target, *pBounds, true);
     fCurrentCmdBuffer->executeCommands(this, buffer);
     fCurrentCmdBuffer->endRenderPass(this);
 
     this->didWriteToSurface(target, &bounds);
 }