Add skia::RefPtr class to wrap ref counted classes from Skia.

ui/gfx/canvas.cc

Index: ui/gfx/canvas.cc
diff --git a/ui/gfx/canvas.cc b/ui/gfx/canvas.cc
index 831f4fc4bf47e9e23a22de519336c43beb1871f7..31934f493f7ba166f9af3142d8d101a08d51f07d 100644
--- a/ui/gfx/canvas.cc
+++ b/ui/gfx/canvas.cc
@@ -140,14 +140,13 @@ void Canvas::DrawDashedRect(const gfx::Rect& rect, SkColor color) {
 
   // Make a shader for the bitmap with an origin of the box we'll draw. This
   // shader is refcounted and will have an initial refcount of 1.
-  SkShader* shader = SkShader::CreateBitmapShader(
+  skia::RefPtr<SkShader> shader = SkShader::CreateBitmapShader(
       *dots, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);
   // Assign the shader to the paint & release our reference. The paint will
   // now own the shader and the shader will be destroyed when the paint goes
   // out of scope.
   SkPaint paint;
-  paint.setShader(shader);
-  shader->unref();
+  paint.setShader(shader.get());
 
   DrawRect(gfx::Rect(rect.x(), rect.y(), rect.width(), 1), paint);
   DrawRect(gfx::Rect(rect.x(), rect.y() + rect.height() - 1, rect.width(), 1),
@@ -373,16 +372,16 @@ void Canvas::DrawImageInt(const gfx::ImageSkia& image,
   shader_scale.preTranslate(SkIntToScalar(-src_x), SkIntToScalar(-src_y));
   shader_scale.postTranslate(SkIntToScalar(dest_x), SkIntToScalar(dest_y));
 
-  SkShader* shader = gfx::CreateImageRepShader(image_rep,
-                                               SkShader::kRepeat_TileMode,
-                                               shader_scale);
+  skia::RefPtr<SkShader> shader = gfx::CreateImageRepShader(
+      image_rep,
+      SkShader::kRepeat_TileMode,
+      shader_scale);
 
   // Set up our paint to use the shader & release our reference (now just owned
   // by the paint).
   SkPaint p(paint);
   p.setFilterBitmap(filter);
-  p.setShader(shader);
-  shader->unref();
+  p.setShader(shader.get());
 
   // The rect will be filled by the bitmap.
   canvas_->drawRect(dest_rect, p);
@@ -399,12 +398,13 @@ void Canvas::DrawImageInPath(const gfx::ImageSkia& image,
 
   SkMatrix matrix;
   matrix.setTranslate(SkIntToScalar(x), SkIntToScalar(y));
-  SkShader* shader = gfx::CreateImageRepShader(image_rep,
-      SkShader::kRepeat_TileMode, matrix);
+  skia::RefPtr<SkShader> shader = gfx::CreateImageRepShader(
+      image_rep,
+      SkShader::kRepeat_TileMode,
+      matrix);
 
   SkPaint p(paint);
-  p.setShader(shader);
-  shader->unref();
+  p.setShader(shader.get());
   canvas_->drawPath(path, p);
 }
 
@@ -465,14 +465,14 @@ void Canvas::TileImageInt(const gfx::ImageSkia& image,
   shader_scale.preTranslate(SkIntToScalar(-src_x), SkIntToScalar(-src_y));
   shader_scale.postTranslate(SkIntToScalar(dest_x), SkIntToScalar(dest_y));
 
-  SkShader* shader = gfx::CreateImageRepShader(image_rep,
-                                               SkShader::kRepeat_TileMode,
-                                               shader_scale);
+  skia::RefPtr<SkShader> shader = gfx::CreateImageRepShader(
+      image_rep,
+      SkShader::kRepeat_TileMode,
+      shader_scale);
 
   SkPaint paint;
-  paint.setShader(shader);
+  paint.setShader(shader.get());
   paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
-  shader->unref();
 
   SkRect dest_rect = { SkIntToScalar(dest_x),
                        SkIntToScalar(dest_y),