Revert r150228 "Add support for PNG representation in gfx::Image"

ui/gfx/image/image.h

Index: ui/gfx/image/image.h
diff --git a/ui/gfx/image/image.h b/ui/gfx/image/image.h
index 079014803a850d21a83672d73d4ddc300ea79843..b643362fcf06376c34705ca94b12f1593feb9c6f 100644
--- a/ui/gfx/image/image.h
+++ b/ui/gfx/image/image.h
@@ -55,7 +55,6 @@ class UI_EXPORT Image {
     kImageRepCocoa,
     kImageRepCairo,
     kImageRepSkia,
-    kImageRepPNG,
   };
 
   typedef std::map<RepresentationType, internal::ImageRep*> RepresentationMap;
@@ -63,12 +62,6 @@ class UI_EXPORT Image {
   // Creates an empty image with no representations.
   Image();
 
-  // Creates a new image by copying the PNG-encoded input for use as the default
-  // representation. For example (from an std::vector):
-  // std::vector<unsigned char> png = ...;
-  // gfx::Image image(&png.front(), png.size());
-  Image(const unsigned char* png, size_t input_size);
-
   // Creates a new image by copying the ImageSkia for use as the default
   // representation.
   explicit Image(const ImageSkia& image);
@@ -105,7 +98,6 @@ class UI_EXPORT Image {
   // Converts the Image to the desired representation and stores it internally.
   // The returned result is a weak pointer owned by and scoped to the life of
   // the Image. Must only be called if IsEmpty() is false.
-  const std::vector<unsigned char>* ToImagePNG() const;
   const SkBitmap* ToSkBitmap() const;
   const ImageSkia* ToImageSkia() const;
 #if defined(TOOLKIT_GTK)
@@ -133,7 +125,6 @@ class UI_EXPORT Image {
   // backing pixels are shared amongst all copies (a fact of each of the
   // converted representations, rather than a limitation imposed by Image) and
   // so the result should be considered immutable.
-  std::vector<unsigned char>* CopyImagePNG() const;
   ImageSkia* CopyImageSkia() const;
   SkBitmap* CopySkBitmap() const;
 #if defined(TOOLKIT_GTK)