clean up printing::Image and printing::Metafile

printing/image.h

Index: printing/image.h
diff --git a/printing/image.h b/printing/image.h
index e055d189587aaba2d05fe458b56b46c64fe25389..7bb3cd78c6683a0f33590334a38a9ce8a4e046d7 100644
--- a/printing/image.h
+++ b/printing/image.h
@@ -21,15 +21,13 @@ class FilePath;
 
 namespace printing {
 
-class Metafile;
-
 // Lightweight raw-bitmap management. The image, once initialized, is immutable.
 // The main purpose is testing image contents.
 class PRINTING_EXPORT Image {
  public:
   // Creates the image from the metafile.  Deduces bounds based on bounds in
   // metafile.  If loading fails size().IsEmpty() will be true.
-  explicit Image(const Metafile& metafile);
+  Image(const void* metafile_src_buffer, size_t metafile_src_buffer_size);
 
   // Copy constructor.
   explicit Image(const Image& image);
@@ -66,13 +64,10 @@ class PRINTING_EXPORT Image {
   }
 
  private:
-  // Construct from metafile.  This is kept internal since it's ambiguous what
-  // kind of data is used (png, bmp, metafile etc).
-  Image(const void* data, size_t size);
-
   bool LoadPng(const std::string& compressed);
 
-  bool LoadMetafile(const Metafile& metafile);
+  bool LoadMetafile(const void* metafile_src_buffer,
+                    size_t metafile_src_buffer_size);
 
   // Pixel dimensions of the image.
   gfx::Size size_;