Get rid of implicit conversion to and from ImageSkiaRep

ui/gfx/image/image_skia_rep.cc

Index: ui/gfx/image/image_skia_rep.cc
diff --git a/ui/gfx/image/image_skia_rep.cc b/ui/gfx/image/image_skia_rep.cc
index be0331a3038780da00a2d7f3a21146c71c6bf8c1..c4c0d9cd3fdf526f4f553ae21e439c9ec7ba3dde 100644
--- a/ui/gfx/image/image_skia_rep.cc
+++ b/ui/gfx/image/image_skia_rep.cc
@@ -25,27 +25,12 @@ ImageSkiaRep::ImageSkiaRep(const gfx::Size& size,
   bitmap_.allocPixels();
 }
 
-ImageSkiaRep::ImageSkiaRep(const SkBitmap& src)
-    : bitmap_(src),
-      scale_factor_(ui::SCALE_FACTOR_NONE) {
-}
-
 ImageSkiaRep::ImageSkiaRep(const SkBitmap& src,
                            ui::ScaleFactor scale_factor)
     : bitmap_(src),
       scale_factor_(scale_factor) {
 }
 
-ImageSkiaRep& ImageSkiaRep::operator=(const SkBitmap& other) {
-  bitmap_ = other;
-  scale_factor_ = ui::SCALE_FACTOR_NONE;
-  return *this;
-}
-
-ImageSkiaRep::operator SkBitmap&() const {
-  return const_cast<SkBitmap&>(bitmap_);
-}
-
 int ImageSkiaRep::GetWidth() const {
   return static_cast<int>(bitmap_.width() /
       ui::GetScaleFactorScale(scale_factor_));