Limit warning message to de-clutter bench output logs

src/core/SkTypeface.cpp

 /*
  * Copyright 2011 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAdvancedTypefaceMetrics.h"
 #include "SkFontDescriptor.h"
 #include "SkFontHost.h"
@@ skipping 235 matching lines @@
 
 SkTypeface* SkTypeface::refMatchingStyle(Style style) const {
     return this->onRefMatchingStyle(style);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////////////////////////
 
 int SkTypeface::onCharsToGlyphs(const void* chars, Encoding encoding,
                                 uint16_t glyphs[], int glyphCount) const {
-    SkDebugf("onCharsToGlyphs unimplemented\n");
+    static bool printed = false;
+    if (!printed) {
+        // Only want to see this message once
+        SkDebugf("\n *** onCharsToGlyphs unimplemented ***\n");
+        printed = true;
+    }
     if (glyphs && glyphCount > 0) {
         sk_bzero(glyphs, glyphCount * sizeof(glyphs[0]));
     }
     return 0;
 }