move SkImageInfo into its own header

src/image/SkImage.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkImagePriv.h"
 #include "SkImage_Base.h"
 
 SK_DEFINE_INST_COUNT(SkImage)
 
-bool operator==(const SkImageInfo& lhs, const SkImageInfo& rhs) {
-    return 0 == memcmp(&lhs, &rhs, sizeof(SkImageInfo));
-}
-bool operator!=(const SkImageInfo& lhs, const SkImageInfo& rhs) {
-    return 0 != memcmp(&lhs, &rhs, sizeof(SkImageInfo));
-}
-
-
 static SkImage_Base* as_IB(SkImage* image) {
     return static_cast<SkImage_Base*>(image);
 }
 
 static const SkImage_Base* as_IB(const SkImage* image) {
     return static_cast<const SkImage_Base*>(image);
 }
 
 uint32_t SkImage::NextUniqueID() {
     static int32_t gUniqueID;
@@ skipping 20 matching lines @@
     return as_IB(this)->onGetTexture();
 }
 
 SkData* SkImage::encode(SkImageEncoder::Type type, int quality) const {
     SkBitmap bm;
     if (as_IB(this)->getROPixels(&bm)) {
         return SkImageEncoder::EncodeData(bm, type, quality);
     }
     return NULL;
 }