Allow soft hyphens in languages without patterns

This patch sets up an "empty" hyphenator, which it uses by default
for locales in which there is no hyphenation pattern data. This has
the effect of enabling soft hyphens (U+00AD), which were otherwise
disabled, because the "no-hyphen" code path didn't consider them.

Bug: 19605972
Change-Id: I4dcb95cee8edc48495f7c38736f5abf26fa04935

core/java/android/text/Hyphenator.java

@@ -45,6 +45,8 @@ public class Hyphenator {
     @GuardedBy("sLock")
     final static HashMap<Locale, Hyphenator> sMap = new HashMap<Locale, Hyphenator>();
 
+    final static Hyphenator sEmptyHyphenator = new Hyphenator(StaticLayout.nLoadHyphenator(""));
+
     final private long mNativePtr;
 
     private Hyphenator(long nativePtr) {
@@ -53,19 +55,19 @@ private Hyphenator(long nativePtr) {
 
     public static long get(@Nullable Locale locale) {
         synchronized (sLock) {
-            if (sMap.containsKey(locale)) {
-                Hyphenator result = sMap.get(locale);
-                return (result == null) ? 0 : result.mNativePtr;
+            Hyphenator result = sMap.get(locale);
+            if (result != null) {
+                return result.mNativePtr;
             }
 
             // TODO: Convert this a proper locale-fallback system
 
             // Fall back to language-only, if available
             Locale languageOnlyLocale = new Locale(locale.getLanguage());
-            if (sMap.containsKey(languageOnlyLocale)) {
-                Hyphenator result = sMap.get(languageOnlyLocale);
+            result = sMap.get(languageOnlyLocale);
+            if (result != null) {
                 sMap.put(locale, result);
-                return (result == null) ? 0 : result.mNativePtr;
+                return result.mNativePtr;
             }
 
             // Fall back to script-only, if available
@@ -75,16 +77,16 @@ public static long get(@Nullable Locale locale) {
                         .setLanguage("und")
                         .setScript(script)
                         .build();
-                if (sMap.containsKey(scriptOnlyLocale)) {
-                    Hyphenator result = sMap.get(scriptOnlyLocale);
+                result = sMap.get(scriptOnlyLocale);
+                if (result != null) {
                     sMap.put(locale, result);
-                    return (result == null) ? 0 : result.mNativePtr;
+                    return result.mNativePtr;
                 }
             }
 
-            sMap.put(locale, null); // To remember we found nothing.
+            sMap.put(locale, sEmptyHyphenator);  // To remember we found nothing.
         }
-        return 0;
+        return sEmptyHyphenator.mNativePtr;
     }
 
     private static Hyphenator loadHyphenator(String languageTag) {