handle no shader from image in drawAtlas

src/core/SkDevice.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorFilter.h"
 #include "SkDevice.h"
 #include "SkDraw.h"
@@ skipping 180 matching lines @@
 
     for (int i = 0; i < count; ++i) {
         SkPoint quad[4];
         xform[i].toQuad(tex[i].width(), tex[i].height(), quad);
         
         SkMatrix localM;
         localM.setRSXform(xform[i]);
         localM.preTranslate(-tex[i].left(), -tex[i].top());
 
         SkPaint pnt(paint);
-        pnt.setShader(atlas->newShader(SkShader::kClamp_TileMode, SkShader::kClamp_TileMode,
-                                       &localM))->unref();
+        SkAutoTUnref<SkShader> shader(atlas->newShader(SkShader::kClamp_TileMode,
+                                                       SkShader::kClamp_TileMode,
+                                                       &localM));
+        if (!shader) {
+            break;
+        }
+        pnt.setShader(shader);
+
         if (colors && colors[i] != SK_ColorWHITE) {
             SkAutoTUnref<SkColorFilter> cf(SkColorFilter::CreateModeFilter(colors[i], mode));
             pnt.setColorFilter(cf);
         }
         
         path.rewind();
         path.addPoly(quad, 4, true);
         path.setConvexity(SkPath::kConvex_Convexity);
         this->drawPath(draw, path, pnt, NULL, true);
     }
@@ skipping 195 matching lines @@
     if (kUnknown_SkPixelGeometry == fSurfaceProps.pixelGeometry()
         || this->onShouldDisableLCD(paint)) {
 
         flags &= ~SkPaint::kLCDRenderText_Flag;
         flags |= SkPaint::kGenA8FromLCD_Flag;
     }
 
     return flags;
 }