Support escaped char codes in WebVTT tokenizer.

Source/core/html/track/vtt/VTTTokenizer.cpp

Index: Source/core/html/track/vtt/VTTTokenizer.cpp
diff --git a/Source/core/html/track/vtt/VTTTokenizer.cpp b/Source/core/html/track/vtt/VTTTokenizer.cpp
index 0d84269f9a0dcba757cd064e0eab6ec0a8f81b9d..5bb06112a987fc794b159ba5aeedac7a6b812c91 100644
--- a/Source/core/html/track/vtt/VTTTokenizer.cpp
+++ b/Source/core/html/track/vtt/VTTTokenizer.cpp
@@ -106,6 +106,7 @@ bool VTTTokenizer::nextToken(VTTToken& token)
         StartTagAnnotationState,
         EndTagState,
         TimestampTagState,
+        EscapeCharacterState,
     } state = DataState;
 
     // 4.8.10.13.4 WebVTT cue text tokenizer
@@ -151,6 +152,9 @@ bool VTTTokenizer::nextToken(VTTToken& token)
                 }
                 buffer.clear();
                 WEBVTT_ADVANCE_TO(DataState);
+            } else if (cc == '#') {
+                buffer.clear();
+                WEBVTT_ADVANCE_TO(EscapeCharacterState);
             } else if (isASCIIAlphanumeric(cc)) {
                 buffer.append(static_cast<LChar>(cc));
                 WEBVTT_ADVANCE_TO(EscapeState);
@@ -174,6 +178,22 @@ bool VTTTokenizer::nextToken(VTTToken& token)
         }
         END_STATE()
 
+        WEBVTT_BEGIN_STATE(EscapeCharacterState) {
+            if (cc == ';') {
+                unsigned charCode = buffer.toString().toUIntStrict();
+                result.append(static_cast<UChar>(charCode));
+                buffer.clear();
+                WEBVTT_ADVANCE_TO(DataState);
+            } else if (WTF::isASCIIDigit(cc)) {
+                buffer.append(static_cast<LChar>(cc));
+                WEBVTT_ADVANCE_TO(EscapeCharacterState);
+            } else {
+                buffer.clear();
+                WEBVTT_ADVANCE_TO(DataState);
+            }
+        }
+        END_STATE()
+
         WEBVTT_BEGIN_STATE(TagState) {
             if (isTokenizerWhitespace(cc)) {
                 ASSERT(result.isEmpty());