Use RefPtr to manage shaders in Gradient and Pattern.

Source/core/platform/graphics/Pattern.cpp

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2013 Google, Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 22 matching lines @@
 #include "SkColorShader.h"
 #include "SkShader.h"
 #include "core/platform/graphics/Image.h"
 
 namespace WebCore {
 
 Pattern::Pattern(PassRefPtr<Image> image, bool repeatX, bool repeatY)
     : m_tileImage(image)
     , m_repeatX(repeatX)
     , m_repeatY(repeatY)
-    , m_pattern(0)
     , m_externalMemoryAllocated(0)
 {
     ASSERT(m_tileImage);
 }
 
 Pattern::~Pattern()
 {
-    SkSafeUnref(m_pattern);
-    m_pattern = 0;
-    if (m_externalMemoryAllocated) {
+    if (m_externalMemoryAllocated)
         v8::V8::AdjustAmountOfExternalAllocatedMemory(-m_externalMemoryAllocated);
-        m_externalMemoryAllocated = 0;
-    }
 }
 
 SkShader* Pattern::shader()
 {
     if (m_pattern)
-        return m_pattern;
+        return m_pattern.get();
 
     RefPtr<NativeImageSkia> image = m_tileImage->nativeImageForCurrentFrame();
     // If we don't have a bitmap, return a transparent shader.
     if (!image)
-        m_pattern = new SkColorShader(SkColorSetARGB(0, 0, 0, 0));
+        m_pattern = adoptRef(new SkColorShader(SK_ColorTRANSPARENT));
     else if (m_repeatX && m_repeatY)
-        m_pattern = SkShader::CreateBitmapShader(image->bitmap(), SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);
+        m_pattern = adoptRef(SkShader::CreateBitmapShader(image->bitmap(), SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode));
     else {
         // Skia does not have a "draw the tile only once" option. Clamp_TileMode
         // repeats the last line of the image after drawing one tile. To avoid
         // filling the space with arbitrary pixels, this workaround forces the
         // image to have a line of transparent pixels on the "repeated" edge(s),
         // thus causing extra space to be transparent filled.
         SkShader::TileMode tileModeX = m_repeatX ? SkShader::kRepeat_TileMode : SkShader::kClamp_TileMode;
         SkShader::TileMode tileModeY = m_repeatY ? SkShader::kRepeat_TileMode : SkShader::kClamp_TileMode;
         int expandW = m_repeatX ? 0 : 1;
         int expandH = m_repeatY ? 0 : 1;
 
         // Create a transparent bitmap 1 pixel wider and/or taller than the
         // original, then copy the orignal into it.
         // FIXME: Is there a better way to pad (not scale) an image in skia?
         SkBitmap bm2;
         bm2.setConfig(image->bitmap().config(), image->bitmap().width() + expandW, image->bitmap().height() + expandH);
         bm2.allocPixels();
         bm2.eraseARGB(0x00, 0x00, 0x00, 0x00);
         SkCanvas canvas(bm2);
         canvas.drawBitmap(image->bitmap(), 0, 0);
         bm2.setImmutable();
-        m_pattern = SkShader::CreateBitmapShader(bm2, tileModeX, tileModeY);
+        m_pattern = adoptRef(SkShader::CreateBitmapShader(bm2, tileModeX, tileModeY));
 
         // Clamp to int, since that's what the adjust function takes.
         m_externalMemoryAllocated = static_cast<int>(std::min(static_cast<size_t>(INT_MAX), bm2.getSafeSize()));
         v8::V8::AdjustAmountOfExternalAllocatedMemory(m_externalMemoryAllocated);
     }
     m_pattern->setLocalMatrix(m_patternSpaceTransformation);
-    return m_pattern;
+    return m_pattern.get();
 }
 
 void Pattern::setPatternSpaceTransform(const AffineTransform& patternSpaceTransformation)
 {
     m_patternSpaceTransformation = patternSpaceTransformation;
     if (m_pattern)
         m_pattern->setLocalMatrix(m_patternSpaceTransformation);
 }
 
 }