fix fontconfig backend to only cache new fonts if their outName was unique

src/ports/SkFontHost_fontconfig.cpp

Index: src/ports/SkFontHost_fontconfig.cpp
diff --git a/src/ports/SkFontHost_fontconfig.cpp b/src/ports/SkFontHost_fontconfig.cpp
index 012ce90c8cdf9f7525da8be9c12e09353061e0a1..0db44b242f41e20440a60c40049d312d3b93c610 100644
--- a/src/ports/SkFontHost_fontconfig.cpp
+++ b/src/ports/SkFontHost_fontconfig.cpp
@@ -109,6 +109,15 @@ SkTypeface* FontConfigTypeface::LegacyCreateTypeface(
         return NULL;
     }
 
+    // check if we, in fact, already have this. perhaps fontconfig aliased the
+    // requested name to some other name we actually have...
+    rec.fFamilyName = outFamilyName.c_str();
+    rec.fStyle = outStyle;
+    face = SkTypefaceCache::FindByProcAndRef(find_proc, &rec);
+    if (face) {
+        return face;
+    }
+
     face = SkNEW_ARGS(FontConfigTypeface, (outStyle, indentity, outFamilyName));
     SkTypefaceCache::Add(face, style);
 //    SkDebugf("add face <%s> <%s> %p [%d]\n", familyName, outFamilyName.c_str(), face, face->getRefCnt());