Add support for CSS unicod encoding to the text codec.

third_party/WebKit/Source/wtf/text/TextCodecICU.cpp

Index: third_party/WebKit/Source/wtf/text/TextCodecICU.cpp
diff --git a/third_party/WebKit/Source/wtf/text/TextCodecICU.cpp b/third_party/WebKit/Source/wtf/text/TextCodecICU.cpp
index b3423597e2e6eee88bcadb6a3b195ea1a56c6b05..b157bf9084e44ddc8a3fe93d2dc316b41d63c3b7 100644
--- a/third_party/WebKit/Source/wtf/text/TextCodecICU.cpp
+++ b/third_party/WebKit/Source/wtf/text/TextCodecICU.cpp
@@ -409,22 +409,37 @@ static UChar fallbackForGBK(UChar32 character)
 }
 #endif
 
-// Invalid character handler when writing escaped entities for unrepresentable
-// characters. See the declaration of TextCodec::encode for more.
-static void urlEscapedEntityCallback(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
-    UChar32 codePoint, UConverterCallbackReason reason, UErrorCode* err)
+// Generic helper for writing escaped entities using the specfied UnencodableHandling.
+static void formatEscapedEntityCallback(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
+    UChar32 codePoint, UConverterCallbackReason reason, UErrorCode* err, UnencodableHandling handling)
 {
     if (reason == UCNV_UNASSIGNED) {
         *err = U_ZERO_ERROR;
 
         UnencodableReplacementArray entity;
-        int entityLen = TextCodec::getUnencodableReplacement(codePoint, URLEncodedEntitiesForUnencodables, entity);
+        int entityLen = TextCodec::getUnencodableReplacement(codePoint, handling, entity);
         ucnv_cbFromUWriteBytes(fromUArgs, entity, entityLen, 0, err);
     } else {
         UCNV_FROM_U_CALLBACK_ESCAPE(context, fromUArgs, codeUnits, length, codePoint, reason, err);
     }
 }
 
+// Invalid character handler when writing escaped entities in CSS encoding for
+// unrepresentable characters. See the declaration of TextCodec::encode for more.
+static void cssEscapedEntityCallback(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
+    UChar32 codePoint, UConverterCallbackReason reason, UErrorCode* err)
+{
+    formatEscapedEntityCallback(context, fromUArgs, codeUnits, length, codePoint, reason, err, CSSEncodedEntitiesForUnencodables);
+}
+
+// Invalid character handler when writing escaped entities in HTML/XML encoding for
+// unrepresentable characters. See the declaration of TextCodec::encode for more.
+static void urlEscapedEntityCallback(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
+    UChar32 codePoint, UConverterCallbackReason reason, UErrorCode* err)
+{
+    formatEscapedEntityCallback(context, fromUArgs, codeUnits, length, codePoint, reason, err, URLEncodedEntitiesForUnencodables);
+}
+
 #if defined(USING_SYSTEM_ICU)
 // Substitutes special GBK characters, escaping all other unassigned entities.
 static void gbkCallbackEscape(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
@@ -440,6 +455,23 @@ static void gbkCallbackEscape(const void* context, UConverterFromUnicodeArgs* fr
     UCNV_FROM_U_CALLBACK_ESCAPE(context, fromUArgs, codeUnits, length, codePoint, reason, err);
 }
 
+// Combines both gbkCssEscapedEntityCallback and GBK character substitution.
+static void gbkCssEscapedEntityCallack(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
+    UChar32 codePoint, UConverterCallbackReason reason, UErrorCode* err)
+{
+    if (reason == UCNV_UNASSIGNED) {
+        if (UChar outChar = fallbackForGBK(codePoint)) {
+            const UChar* source = &outChar;
+            *err = U_ZERO_ERROR;
+            ucnv_cbFromUWriteUChars(fromUArgs, &source, source + 1, 0, err);
+            return;
+        }
+        cssEscapedEntityCallback(context, fromUArgs, codeUnits, length, codePoint, reason, err);
+        return;
+    }
+    UCNV_FROM_U_CALLBACK_ESCAPE(context, fromUArgs, codeUnits, length, codePoint, reason, err);
+}
+
 // Combines both gbkUrlEscapedEntityCallback and GBK character substitution.
 static void gbkUrlEscapedEntityCallack(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
     UChar32 codePoint, UConverterCallbackReason reason, UErrorCode* err)
@@ -527,6 +559,13 @@ CString TextCodecICU::encodeInternal(const TextCodecInput& input, UnencodableHan
         ucnv_setFromUCallBack(m_converterICU, m_needsGBKFallbacks ? gbkUrlEscapedEntityCallack : urlEscapedEntityCallback, 0, 0, 0, &err);
 #endif
         break;
+    case CSSEncodedEntitiesForUnencodables:
+#if !defined(USING_SYSTEM_ICU)
+        ucnv_setFromUCallBack(m_converterICU, cssEscapedEntityCallback, 0, 0, 0, &err);
+#else
+        ucnv_setFromUCallBack(m_converterICU, m_needsGBKFallbacks ? gbkCssEscapedEntityCallack : cssEscapedEntityCallback, 0, 0, 0, &err);
+#endif
+        break;
     }
 
     ASSERT(U_SUCCESS(err));