[Fetch] Always use utf-8 for decoding in text()

third_party/WebKit/Source/core/html/parser/TextResourceDecoder.cpp

Index: third_party/WebKit/Source/core/html/parser/TextResourceDecoder.cpp
diff --git a/third_party/WebKit/Source/core/html/parser/TextResourceDecoder.cpp b/third_party/WebKit/Source/core/html/parser/TextResourceDecoder.cpp
index 7b74f86b64e4e7c192faaa86dd82ed94154c943d..be1084d5d3d248bbafa37fd22df25591c18dcdd0 100644
--- a/third_party/WebKit/Source/core/html/parser/TextResourceDecoder.cpp
+++ b/third_party/WebKit/Source/core/html/parser/TextResourceDecoder.cpp
@@ -111,7 +111,7 @@ const WTF::TextEncoding& TextResourceDecoder::defaultEncoding(ContentType conten
     return specifiedDefaultEncoding;
 }
 
-TextResourceDecoder::TextResourceDecoder(const String& mimeType, const WTF::TextEncoding& specifiedDefaultEncoding, bool usesEncodingDetector)
+TextResourceDecoder::TextResourceDecoder(const String& mimeType, const WTF::TextEncoding& specifiedDefaultEncoding, EncodingDetectionOption encodingDetectionOption)
     : m_contentType(determineContentType(mimeType))
     , m_encoding(defaultEncoding(m_contentType, specifiedDefaultEncoding))
     , m_source(DefaultEncoding)
@@ -122,8 +122,10 @@ TextResourceDecoder::TextResourceDecoder(const String& mimeType, const WTF::Text
     , m_checkedForMetaCharset(false)
     , m_useLenientXMLDecoding(false)
     , m_sawError(false)
-    , m_usesEncodingDetector(usesEncodingDetector)
+    , m_encodingDetectionOption(encodingDetectionOption)
 {
+    if (m_encodingDetectionOption == AlwaysUseUTF8ForText)
+        ASSERT(m_contentType == PlainTextContent && m_encoding == UTF8Encoding());
 }
 
 TextResourceDecoder::~TextResourceDecoder()
@@ -209,23 +211,25 @@ size_t TextResourceDecoder::checkForBOM(const char* data, size_t len)
     unsigned char c4 = buf2Len ? (--buf2Len, *buf2++) : 0;
 
     // Check for the BOM.
-    if (c1 == 0xFF && c2 == 0xFE) {
-        if (c3 || c4) {
-            setEncoding(UTF16LittleEndianEncoding(), AutoDetectedEncoding);
+    if (c1 == 0xEF && c2 == 0xBB && c3 == 0xBF) {
+        setEncoding(UTF8Encoding(), AutoDetectedEncoding);
+        lengthOfBOM = 3;
+    } else if (m_encodingDetectionOption != AlwaysUseUTF8ForText) {
+        if (c1 == 0xFF && c2 == 0xFE) {
+            if (c3 || c4) {
+                setEncoding(UTF16LittleEndianEncoding(), AutoDetectedEncoding);
+                lengthOfBOM = 2;
+            } else {
+                setEncoding(UTF32LittleEndianEncoding(), AutoDetectedEncoding);
+                lengthOfBOM = 4;
+            }
+        } else if (c1 == 0xFE && c2 == 0xFF) {
+            setEncoding(UTF16BigEndianEncoding(), AutoDetectedEncoding);
             lengthOfBOM = 2;
-        } else {
-            setEncoding(UTF32LittleEndianEncoding(), AutoDetectedEncoding);
+        } else if (!c1 && !c2 && c3 == 0xFE && c4 == 0xFF) {
+            setEncoding(UTF32BigEndianEncoding(), AutoDetectedEncoding);
             lengthOfBOM = 4;
         }
-    } else if (c1 == 0xEF && c2 == 0xBB && c3 == 0xBF) {
-        setEncoding(UTF8Encoding(), AutoDetectedEncoding);
-        lengthOfBOM = 3;
-    } else if (c1 == 0xFE && c2 == 0xFF) {
-        setEncoding(UTF16BigEndianEncoding(), AutoDetectedEncoding);
-        lengthOfBOM = 2;
-    } else if (!c1 && !c2 && c3 == 0xFE && c4 == 0xFF) {
-        setEncoding(UTF32BigEndianEncoding(), AutoDetectedEncoding);
-        lengthOfBOM = 4;
     }
 
     if (lengthOfBOM || bufferLength + len >= 4)
@@ -359,7 +363,7 @@ bool TextResourceDecoder::shouldAutoDetect() const
 {
     // Just checking m_hintEncoding suffices here because it's only set
     // in setHintEncoding when the source is AutoDetectedEncoding.
-    return m_usesEncodingDetector
+    return m_encodingDetectionOption == UseAllAutoDetection
         && (m_source == DefaultEncoding || (m_source == EncodingFromParentFrame && m_hintEncoding));
 }