Ensure that SkDebugf is exported from the library.

This was caused by the change to always call SkDebugf() in SkASSERT(). There are many headers in Skia that call SkASSERT and so we were seeing linking issues in Gecko where we were using Skia across DLL boundaries.

R=reed@google.com, bsalomon@google.com, reed1
BUG=skia:

Author: george@mozilla.com

Review URL: https://codereview.chromium.org/438783002
1 file changed