handle null vertex or index buffers in batch

src/gpu/GrTessellatingPathRenderer.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 "GrTessellatingPathRenderer.h"
 
 #include "GrBatch.h"
@@ skipping 1497 matching lines @@
             }
         }
 
         size_t stride = gp->getVertexStride();
         const GrVertexBuffer* vertexBuffer;
         int firstVertex;
         void* vertices = batchTarget->vertexPool()->makeSpace(stride,
                                                               count,
                                                               &vertexBuffer,
                                                               &firstVertex);
+
+        if (!vertices) {
+            SkDebugf("Could not allocate vertices\n");
+            return;
+        }
+
         LOG("emitting %d verts\n", count);
         void* end = polys_to_triangles(polys, fillType, vertices);
         int actualCount = static_cast<int>(
             (static_cast<char*>(end) - static_cast<char*>(vertices)) / stride);
         LOG("actual count: %d\n", actualCount);
         SkASSERT(actualCount <= count);
 
         GrPrimitiveType primitiveType = WIREFRAME ? kLines_GrPrimitiveType
                                                   : kTriangles_GrPrimitiveType;
         GrDrawTarget::DrawInfo drawInfo;
@@ skipping 51 matching lines @@
     SkMatrix vmi;
     if (!viewM.invert(&vmi)) {
         return false;
     }
     vmi.mapRect(&clipBounds);
     SkAutoTUnref<GrBatch> batch(TessellatingPathBatch::Create(color, path, viewM, clipBounds));
     target->drawBatch(pipelineBuilder, batch);
 
     return true;
 }