add colortable enum to SkImage to ease interop between it and SkBitmap::Config

src/image/SkImagePriv.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 "SkImagePriv.h"
 #include "SkCanvas.h"
 #include "SkPicture.h"
 
 SkBitmap::Config SkImageInfoToBitmapConfig(const SkImageInfo& info) {
     switch (info.fColorType) {
         case kAlpha_8_SkColorType:
             return SkBitmap::kA8_Config;
 
         case kRGB_565_SkColorType:
             return SkBitmap::kRGB_565_Config;
 
         case kPMColor_SkColorType:
             return SkBitmap::kARGB_8888_Config;
 
+        case kIndex8_SkColorType:
+            return SkBitmap::kIndex8_Config;
+
         default:
             // break for unsupported colortypes
             break;
     }
     return SkBitmap::kNo_Config;
 }
 
 int SkImageBytesPerPixel(SkColorType ct) {
     static const uint8_t gColorTypeBytesPerPixel[] = {
         1,  // kAlpha_8_SkColorType
         2,  // kRGB_565_SkColorType
         4,  // kRGBA_8888_SkColorType
         4,  // kBGRA_8888_SkColorType
         4,  // kPMColor_SkColorType
+        1,  // kIndex8_SkColorType
     };
 
     SkASSERT((size_t)ct < SK_ARRAY_COUNT(gColorTypeBytesPerPixel));
     return gColorTypeBytesPerPixel[ct];
 }
 
 bool SkBitmapToImageInfo(const SkBitmap& bm, SkImageInfo* info) {
     switch (bm.config()) {
         case SkBitmap::kA8_Config:
             info->fColorType = kAlpha_8_SkColorType;
             break;
-
+            
+        case SkBitmap::kIndex8_Config:
+            info->fColorType = kIndex8_SkColorType;
+            break;
+            
         case SkBitmap::kRGB_565_Config:
             info->fColorType = kRGB_565_SkColorType;
             break;
 
         case SkBitmap::kARGB_8888_Config:
             info->fColorType = kPMColor_SkColorType;
             break;
 
         default:
             return false;
@@ skipping 74 matching lines @@
         canvas->save();
     }
     canvas->concat(matrix);
     if (!paint || !needs_layer(*paint)) {
         canvas->clipRect(tmpSrc);
     }
 
     canvas->drawPicture(*picture);
     canvas->restoreToCount(saveCount);
 }