move SkImageInfo into its own header

include/core/SkImage.h

Index: include/core/SkImage.h
diff --git a/include/core/SkImage.h b/include/core/SkImage.h
index 39f2ec931e4548bc1367e055854b7367e7ded54f..accfc0db790346a3330e1f84cf02668631e45910 100644
--- a/include/core/SkImage.h
+++ b/include/core/SkImage.h
@@ -8,7 +8,7 @@
 #ifndef SkImage_DEFINED
 #define SkImage_DEFINED
 
-#include "SkAlpha.h"
+#include "SkImageInfo.h"
 #include "SkImageEncoder.h"
 #include "SkRefCnt.h"
 #include "SkScalar.h"
@@ -23,34 +23,6 @@ class GrTexture;
 // need for TileMode
 #include "SkShader.h"
 
-enum SkColorType {
-    kAlpha_8_SkColorType,
-    kRGB_565_SkColorType,
-    kRGBA_8888_SkColorType,
-    kBGRA_8888_SkColorType,
-
-#if SK_PMCOLOR_BYTE_ORDER(B,G,R,A)
-    kPMColor_SkColorType = kBGRA_8888_SkColorType,
-#elif SK_PMCOLOR_BYTE_ORDER(R,G,B,A)
-    kPMColor_SkColorType = kRGBA_8888_SkColorType,
-#else
-    #error "SK_*32_SHFIT values must correspond to BGRA or RGBA byte order"
-#endif
-
-    kIndex8_SkColorType,
-    kLastEnum_SkColorType = kIndex8_SkColorType
-};
-
-struct SkImageInfo {
-    int         fWidth;
-    int         fHeight;
-    SkColorType fColorType;
-    SkAlphaType fAlphaType;
-};
-
-bool operator==(const SkImageInfo& lhs, const SkImageInfo& rhs);
-bool operator!=(const SkImageInfo& lhs, const SkImageInfo& rhs);
-
 /**
  *  SkImage is an abstraction for drawing a rectagle of pixels, though the
  *  particular type of image could be actually storing its data on the GPU, or