use colortype instead of config

patch from issue 172063004

BUG=skia:
R=scroggo@google.com

Review URL: https://codereview.chromium.org/173893002

git-svn-id: http://skia.googlecode.com/svn/trunk@13520 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index 4462b4c..93dc14b 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -518,7 +518,7 @@
     inc_canvas();
 
     SkBitmap bitmap;
-    bitmap.setConfig(SkBitmap::kNo_Config, width, height);
+    bitmap.setConfig(SkImageInfo::MakeUnknown(width, height));
     this->init(SkNEW_ARGS(SkBitmapDevice, (bitmap)))->unref();
 }
 
@@ -950,9 +950,7 @@
     if (dev) {
         return dev->imageInfo();
     } else {
-        // TODO: need a real unknown for alphatype it seems.
-        SkAlphaType unknownAlphaType = kIgnore_SkAlphaType;
-        return SkImageInfo::Make(0, 0, kUnknown_SkColorType, unknownAlphaType);
+        return SkImageInfo::MakeUnknown(0, 0);
     }
 }