Remove SK_SUPPORT_LEGACY_GET_PIXELS_ENUM.

SK_SUPPORT_LEGACY_GET_PIXELS_ENUM just set a \#define to convert
onGetPixelsEnum
to
onGetPixels

Now that Chrome has been updated to override onGetPixels, there is no
need for the define.

BUG=skia:3257

Review URL: https://codereview.chromium.org/933853004
diff --git a/gyp/skia_for_chromium_defines.gypi b/gyp/skia_for_chromium_defines.gypi
index 6d10ac2..bcc6096 100644
--- a/gyp/skia_for_chromium_defines.gypi
+++ b/gyp/skia_for_chromium_defines.gypi
@@ -14,7 +14,6 @@
     #
     'skia_for_chromium_defines': [
       'SK_LEGACY_DRAWPICTURECALLBACK',
-      'SK_SUPPORT_LEGACY_GET_PIXELS_ENUM',
     ],
   },
 }
diff --git a/include/core/SkImageGenerator.h b/include/core/SkImageGenerator.h
index 4e89d76..5de9d3d 100644
--- a/include/core/SkImageGenerator.h
+++ b/include/core/SkImageGenerator.h
@@ -15,12 +15,6 @@
 class SkData;
 class SkImageGenerator;
 
-//#define SK_SUPPORT_LEGACY_GET_PIXELS_ENUM
-
-#ifdef SK_SUPPORT_LEGACY_GET_PIXELS_ENUM
-    #define onGetPixelsEnum onGetPixels
-#endif
-
 /**
  *  Takes ownership of SkImageGenerator.  If this method fails for
  *  whatever reason, it will return false and immediatetely delete