Revert "remove SK_SUPPORT_LEGACY_BUILDMIPMAP"

This reverts commit 9acd04797101990af23f5c374b7dfcbaac12fd2b.

git-svn-id: http://skia.googlecode.com/svn/trunk@14685 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/skia_for_chromium_defines.gypi b/gyp/skia_for_chromium_defines.gypi
index 1bbd0c3..2702e35 100644
--- a/gyp/skia_for_chromium_defines.gypi
+++ b/gyp/skia_for_chromium_defines.gypi
@@ -16,6 +16,7 @@
       'SK_SUPPORT_LEGACY_PUBLICEFFECTCONSTRUCTORS=1',
       'SK_SUPPORT_LEGACY_GETTOPDEVICE',
       'SK_SUPPORT_LEGACY_N32_NAME',
+      'SK_SUPPORT_LEGACY_BUILDMIPMAP',
     ],
   },
 }