Fix minor memory leaks

gm/shallowgradient.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 #include "SkGradientShader.h"
 
@@ skipping 40 matching lines @@
     }
 
     virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
         const SkColor colors[] = { 0xFF555555, 0xFF444444 };
         const int colorCount = SK_ARRAY_COUNT(colors);
 
         SkRect r = { 0, 0, this->width(), this->height() };
         SkSize size = SkSize::Make(r.width(), r.height());
 
         SkPaint paint;
-        paint.setShader(fProc(colors, colorCount, size));
+        paint.setShader(fProc(colors, colorCount, size))->unref();
         canvas->drawRect(r, paint);
     }
 
 private:
     MakeShaderProc fProc;
     SkString fName;
 
     typedef skiagm::GM INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 DEF_GM( return new ShallowGradientGM(shader_linear, "linear"); )
 DEF_GM( return new ShallowGradientGM(shader_radial, "radial"); )
 DEF_GM( return new ShallowGradientGM(shader_conical, "conical"); )
 DEF_GM( return new ShallowGradientGM(shader_sweep, "sweep"); )