handle null vertex or index buffers in batch

src/gpu/effects/GrDashingEffect.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrDashingEffect.h"
 
 #include "GrBatch.h"
@@ skipping 518 matching lines @@
 
         const GrVertexBuffer* vertexBuffer;
         int firstVertex;
 
         size_t vertexStride = gp->getVertexStride();
         void* vertices = batchTarget->vertexPool()->makeSpace(vertexStride,
                                                               totalRectCount * kVertsPerDash,
                                                               &vertexBuffer,
                                                               &firstVertex);
 
+        if (!vertices || !batchTarget->quadIndexBuffer()) {
+            SkDebugf("Could not allocate buffers\n");
+            return;
+        }
+
         int curVIdx = 0;
         int rectIndex = 0;
         for (int i = 0; i < instanceCount; i++) {
             Geometry& args = fGeoData[i];
 
             if (!draws[i].fLineDone) {
                 if (fullDash) {
                     setup_dashed_rect(rects[rectIndex], vertices, curVIdx, args.fSrcRotInv,
                                       draws[i].fStartOffset, draws[i].fDevBloat,
                                       draws[i].fLineLength, draws[i].fHalfDevStroke,
@@ skipping 703 matching lines @@
     switch (cap) {
         case kRound_DashCap:
             return DashingCircleEffect::Create(color, edgeType, localMatrix);
         case kNonRound_DashCap:
             return DashingLineEffect::Create(color, edgeType, localMatrix);
         default:
             SkFAIL("Unexpected dashed cap.");
     }
     return NULL;
 }