remove unused device::eraseColor

include/core/SkDevice.h

Index: include/core/SkDevice.h
diff --git a/include/core/SkDevice.h b/include/core/SkDevice.h
index 3c26baca5b012da04a84b38b470f926e6bb279dc..833e452fab93f6213b5bcfcd06cd41ffdbefcfcc 100644
--- a/include/core/SkDevice.h
+++ b/include/core/SkDevice.h
@@ -166,9 +166,6 @@ protected:
      */
     virtual void clear(SkColor color) = 0;
 
-    SK_ATTR_DEPRECATED("use clear() instead")
-    void eraseColor(SkColor eraseColor) { this->clear(eraseColor); }
-
     /** These are called inside the per-device-layer loop for each draw call.
      When these are called, we have already applied any saveLayer operations,
      and are handling any looping from the paint, and any effects from the