fix for perf regression on ugamsolutions / msaa16

src/gpu/GrAtlasTextContext.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 "GrAtlasTextContext.h"
 
 #include "GrAtlas.h"
 #include "GrBatch.h"
@@ skipping 683 matching lines @@
 
     void generateGeometry(GrBatchTarget* batchTarget, const GrPipeline* pipeline) override {
         // if we have RGB, then we won't have any SkShaders so no need to use a localmatrix.
         // TODO actually only invert if we don't have RGBA
         SkMatrix localMatrix;
         if (this->usesLocalCoords() && !this->viewMatrix().invert(&localMatrix)) {
             SkDebugf("Cannot invert viewmatrix\n");
             return;
         }
 
+        GrTexture* texture = fFontCache->getTexture(fMaskFormat);
+        if (!texture) {
+            SkDebugf("Could not allocate backing texture for atlas\n");
+            return;
+        }
+
         GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kNone_FilterMode);
 
         // This will be ignored in the non A8 case
         bool opaqueVertexColors = GrColorIsOpaque(this->color());
         SkAutoTUnref<const GrGeometryProcessor> gp(
                 GrBitmapTextGeoProc::Create(this->color(),
-                                            fFontCache->getTexture(fMaskFormat),
+                                            texture,
                                             params,
                                             fMaskFormat,
                                             opaqueVertexColors,
                                             localMatrix));
 
         size_t vertexStride = gp->getVertexStride();
         SkASSERT(vertexStride == get_vertex_stride(fMaskFormat));
 
         this->initDraw(batchTarget, gp, pipeline);
 
@@ skipping 372 matching lines @@
 
     GrColor color = grPaint.getColor();
     uint8_t paintAlpha = skPaint.getAlpha();
     for (int run = 0; run < cacheBlob->fRunCount; run++) {
         this->flushRun(target, &pipelineBuilder, cacheBlob, run, color, paintAlpha);
     }
 
     // Now flush big glyphs
     this->flushBigGlyphs(cacheBlob, rt, grPaint, clip);
 }