Fix bug #5822825 Paint.measureText (char[] text, int index, int count) cannot handle text more than 32K long

- do not clear the smart pointer when the cache entry does not fit the cache size

Change-Id: I49f1aa1e70018bb7d6a8fb076d9269d0ec6a5d98
See: http://code.google.com/p/android/issues/detail?id=23337

core/jni/android/graphics/TextLayoutCache.cpp

@@ -176,7 +176,6 @@ sp<TextLayoutCacheValue> TextLayoutCache::getValue(SkPaint* paint,
                         value->getElapsedTime() * 0.000001f,
                         String8(text + start, count).string());
             }
-            value.clear();
         }
     } else {
         // This is a cache hit, just log timestamp and user infos