Limit lifetime of GrDrawContext objects

src/gpu/GrBlurUtils.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 "GrBlurUtils.h"
 #include "GrDrawContext.h"
 #include "GrCaps.h"
@@ skipping 104 matching lines @@
         desc.fConfig = kAlpha_8_GrPixelConfig;
     }
 
     GrTexture* mask = context->textureProvider()->createApproxTexture(desc);
     if (nullptr == mask) {
         return nullptr;
     }
 
     SkRect clipRect = SkRect::MakeWH(maskRect.width(), maskRect.height());
 
-    GrDrawContext* drawContext = context->drawContext();
+    SkAutoTUnref<GrDrawContext> drawContext(context->drawContext());
     if (!drawContext) {
         return nullptr;
     }
 
     drawContext->clear(mask->asRenderTarget(), nullptr, 0x0, true);
 
     GrPaint tempPaint;
     tempPaint.setAntiAlias(doAA);
     tempPaint.setCoverageSetOpXPFactory(SkRegion::kReplace_Op);
 
@@ skipping 150 matching lines @@
                                                               SkPaint::kFill_Style;
         draw_with_mask_filter(drawContext, context->textureProvider(), renderTarget,
                               clip, viewMatrix, *devPathPtr,
                               paint.getMaskFilter(), clipBounds, &grPaint, style);
         return;
     }
 
     drawContext->drawPath(renderTarget, clip, grPaint, viewMatrix, *pathPtr, strokeInfo);
 }