hide SkDevice::config()

TBR=robertphilips

Author: reed@chromium.org

Review URL: https://codereview.chromium.org/302253002
diff --git a/src/utils/SkDeferredCanvas.cpp b/src/utils/SkDeferredCanvas.cpp
index 9f444e1..a517472 100644
--- a/src/utils/SkDeferredCanvas.cpp
+++ b/src/utils/SkDeferredCanvas.cpp
@@ -159,7 +159,9 @@
 
     virtual int width() const SK_OVERRIDE;
     virtual int height() const SK_OVERRIDE;
+#ifdef SK_SUPPORT_LEGACY_DEVICE_CONFIG
     virtual SkBitmap::Config config() const SK_OVERRIDE;
+#endif
     virtual bool isOpaque() const SK_OVERRIDE;
     virtual SkImageInfo imageInfo() const SK_OVERRIDE;
 
@@ -435,9 +437,11 @@
     return immediateDevice()->height();
 }
 
+#ifdef SK_SUPPORT_LEGACY_DEVICE_CONFIG
 SkBitmap::Config SkDeferredDevice::config() const {
     return immediateDevice()->config();
 }
+#endif
 
 bool SkDeferredDevice::isOpaque() const {
     return immediateDevice()->isOpaque();