allow createScalerContext to return null, and then have the GDI backend trigger that if we fail to …

src/core/SkScalerContext.cpp

 
 /*
  * Copyright 2006 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 "SkScalerContext.h"
@@ skipping 834 matching lines @@
             sk_bzero(mx, sizeof(*mx));
         }
         if (my) {
             sk_bzero(my, sizeof(*my));
         }
     }
 };
 
 extern SkScalerContext* SkCreateColorScalerContext(const SkDescriptor* desc);
 
-SkScalerContext* SkTypeface::createScalerContext(const SkDescriptor* desc) const {
-    SkScalerContext* c = NULL;  //SkCreateColorScalerContext(desc);
-    if (NULL == c) {
-        c = this->onCreateScalerContext(desc);
-    }
-    if (NULL == c) {
+SkScalerContext* SkTypeface::createScalerContext(const SkDescriptor* desc,
+                                                 bool allowFailure) const {
+    SkScalerContext* c = this->onCreateScalerContext(desc);
+
+    if (!c && !allowFailure) {
         c = SkNEW_ARGS(SkScalerContext_Empty,
                        (const_cast<SkTypeface*>(this), desc));
     }
     return c;
 }
+