Do not break after ZWJ if the trailing character is Emoji.

third_party/WebKit/Source/platform/text/Character.h

Index: third_party/WebKit/Source/platform/text/Character.h
diff --git a/third_party/WebKit/Source/platform/text/Character.h b/third_party/WebKit/Source/platform/text/Character.h
index 2f64ac543ad5e6217906e55d4da5c76e116f56a0..5ca5136ff1c86789937a0d3af7688d802c7aa127 100644
--- a/third_party/WebKit/Source/platform/text/Character.h
+++ b/third_party/WebKit/Source/platform/text/Character.h
@@ -112,6 +112,9 @@ public:
         return u_hasBinaryProperty(c, UCHAR_GRAPHEME_EXTEND);
     }
 
+    // Returns true if the character has a Emoji property.
+    // See http://www.unicode.org/Public/emoji/3.0/emoji-data.txt
+    static bool isEmoji(UChar32);
     // Default presentation style according to:
     // http://www.unicode.org/reports/tr51/#Presentation_Style
     static bool isEmojiTextDefault(UChar32);