make info real in SkPixelRef, and add bitmap::asImageInfo

include/core/SkImageInfo.h

Index: include/core/SkImageInfo.h
diff --git a/include/core/SkImageInfo.h b/include/core/SkImageInfo.h
index c22249b842aaf3f602c5e3b99e57ce1bdaff7b42..1165479f7484267e47dc5dfa2bba90e5a79dce56 100644
--- a/include/core/SkImageInfo.h
+++ b/include/core/SkImageInfo.h
@@ -10,6 +10,9 @@
 
 #include "SkTypes.h"
 
+class SkFlattenableWriteBuffer;
+class SkFlattenableReadBuffer;
+
 /**
  *  Describes how to interpret the alpha compoent of a pixel.
  */
@@ -63,11 +66,12 @@ static inline bool SkAlphaTypeIsOpaque(SkAlphaType at) {
 enum SkColorType {
     kAlpha_8_SkColorType,
     kRGB_565_SkColorType,
+    kARGB_4444_SkColorType,
     kRGBA_8888_SkColorType,
     kBGRA_8888_SkColorType,
-    kIndex8_SkColorType,
+    kIndex_8_SkColorType,
 
-    kLastEnum_SkColorType = kIndex8_SkColorType,
+    kLastEnum_SkColorType = kIndex_8_SkColorType,
 
 #if SK_PMCOLOR_BYTE_ORDER(B,G,R,A)
     kPMColor_SkColorType = kBGRA_8888_SkColorType
@@ -82,6 +86,7 @@ static int SkColorTypeBytesPerPixel(SkColorType ct) {
     static const uint8_t gSize[] = {
         1,  // Alpha_8
         2,  // RGB_565
+        2,  // ARGB_4444
         4,  // RGBA_8888
         4,  // BGRA_8888
         1,  // kIndex_8
@@ -112,12 +117,26 @@ struct SkImageInfo {
         return SkColorTypeBytesPerPixel(fColorType);
     }
 
+    size_t minRowBytes() const {
+        return fWidth * this->bytesPerPixel();
+    }
+
     bool operator==(const SkImageInfo& other) const {
         return 0 == memcmp(this, &other, sizeof(other));
     }
     bool operator!=(const SkImageInfo& other) const {
         return 0 != memcmp(this, &other, sizeof(other));
     }
+
+    void unflatten(SkFlattenableReadBuffer&);
+    void flatten(SkFlattenableWriteBuffer&) const;
+
+    size_t getSafeSize(size_t rowBytes) const {
+        if (0 == fHeight) {
+            return 0;
+        }
+        return (fHeight - 1) * rowBytes + fWidth * this->bytesPerPixel();
+    }
 };
 
 #endif