Change device factories to take SkImageInfo instead of SkBitmap::Config

patch from issue 167033002

BUG=skia:
R=reed@google.com

Author: reed@chromium.org

Review URL: https://codereview.chromium.org/168653002

git-svn-id: http://skia.googlecode.com/svn/trunk@13463 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index 4be092a..aaaeb3b 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -1124,8 +1124,7 @@
     friend class SkDrawIter;    // needs setupDrawForLayerDevice()
     friend class AutoDrawLooper;
 
-    SkBaseDevice* createLayerDevice(SkBitmap::Config, int width, int height,
-                                    bool isOpaque);
+    SkBaseDevice* createLayerDevice(const SkImageInfo&);
 
     SkBaseDevice* init(SkBaseDevice*);