Check for NULL familyName in SkFontMgr_fontconfig.

src/ports/SkFontMgr_fontconfig.cpp

Index: src/ports/SkFontMgr_fontconfig.cpp
diff --git a/src/ports/SkFontMgr_fontconfig.cpp b/src/ports/SkFontMgr_fontconfig.cpp
index 58597d93952bcc07a630c1c9a8a85f1445df13bc..f03e5acaf1382d50fc6ababd4d682f7cabacd632 100644
--- a/src/ports/SkFontMgr_fontconfig.cpp
+++ b/src/ports/SkFontMgr_fontconfig.cpp
@@ -771,10 +771,12 @@ protected:
         FCLocker lock;
 
         SkAutoFcPattern pattern;
-        FcValue familyNameValue;
-        familyNameValue.type = FcTypeString;
-        familyNameValue.u.s = reinterpret_cast<const FcChar8*>(familyName);
-        FcPatternAddWeak(pattern, FC_FAMILY, familyNameValue, FcFalse);
+        if (familyName) {
+            FcValue familyNameValue;
+            familyNameValue.type = FcTypeString;
+            familyNameValue.u.s = reinterpret_cast<const FcChar8*>(familyName);
+            FcPatternAddWeak(pattern, FC_FAMILY, familyNameValue, FcFalse);
+        }
         fcpattern_from_skfontstyle(style, pattern);
 
         SkAutoFcCharSet charSet;