expose CGImage -> SkBitmap

BUG=skia:
R=scroggo@google.com, halcanary@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/243463005

git-svn-id: http://skia.googlecode.com/svn/trunk@14315 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkBitmap.cpp b/src/core/SkBitmap.cpp
index 2a8c8e4..d19e9ca 100644
--- a/src/core/SkBitmap.cpp
+++ b/src/core/SkBitmap.cpp
@@ -997,7 +997,8 @@
     switch (dstColorType) {
         case kAlpha_8_SkColorType:
         case kRGB_565_SkColorType:
-        case kN32_SkColorType:
+        case kRGBA_8888_SkColorType:
+        case kBGRA_8888_SkColorType:
             break;
         case kIndex_8_SkColorType:
             if (!sameConfigs) {