Make the use of fallback fonts in Android a runtime decision.

src/core/SkPaintOptionsAndroid.cpp

Index: src/core/SkPaintOptionsAndroid.cpp
diff --git a/src/core/SkPaintOptionsAndroid.cpp b/src/core/SkPaintOptionsAndroid.cpp
index 7bf6fc44cd020ce269c865b10527625522b4a2dd..a08845a0b447a8c4a8ecacc45718434095db9df2 100644
--- a/src/core/SkPaintOptionsAndroid.cpp
+++ b/src/core/SkPaintOptionsAndroid.cpp
@@ -30,6 +30,7 @@ SkLanguage SkLanguage::getParent() const {
 void SkPaintOptionsAndroid::flatten(SkFlattenableWriteBuffer& buffer) const {
     buffer.writeUInt(fFontVariant);
     buffer.writeString(fLanguage.getTag().c_str());
+    buffer.writeBool(fUseFontFallbacks);
 }
 
 void SkPaintOptionsAndroid::unflatten(SkFlattenableReadBuffer& buffer) {
@@ -37,6 +38,7 @@ void SkPaintOptionsAndroid::unflatten(SkFlattenableReadBuffer& buffer) {
     char* tag = buffer.readString();
     fLanguage = SkLanguage(tag);
     sk_free(tag);
+    fUseFontFallbacks = buffer.readBool();
 }
 
 #endif