Replace the type of hint url for blink::detectTextEncoding

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

Index: third_party/WebKit/Source/core/html/parser/TextResourceDecoder.h
diff --git a/third_party/WebKit/Source/core/html/parser/TextResourceDecoder.h b/third_party/WebKit/Source/core/html/parser/TextResourceDecoder.h
index a7cc4e80f682d482ff2e5e4cacdff3092f3e739e..2d929736b1b3fcab37bc2440d7dcb9c2a431d37f 100644
--- a/third_party/WebKit/Source/core/html/parser/TextResourceDecoder.h
+++ b/third_party/WebKit/Source/core/html/parser/TextResourceDecoder.h
@@ -23,10 +23,11 @@
 #ifndef TextResourceDecoder_h
 #define TextResourceDecoder_h
 
+#include <memory>
 #include "core/CoreExport.h"
+#include "platform/weborigin/KURL.h"
 #include "wtf/PtrUtil.h"
 #include "wtf/text/TextEncoding.h"
-#include <memory>
 
 namespace blink {
 
@@ -52,13 +53,13 @@ class CORE_EXPORT TextResourceDecoder {
       const String& mimeType,
       const WTF::TextEncoding& defaultEncoding = WTF::TextEncoding()) {
     return WTF::wrapUnique(new TextResourceDecoder(
-        mimeType, defaultEncoding, UseContentAndBOMBasedDetection, String()));
+        mimeType, defaultEncoding, UseContentAndBOMBasedDetection, KURL()));
   }
 
   static std::unique_ptr<TextResourceDecoder> createWithAutoDetection(
       const String& mimeType,
       const WTF::TextEncoding& defaultEncoding,
-      const String& url) {
+      const KURL& url) {
     return WTF::wrapUnique(new TextResourceDecoder(mimeType, defaultEncoding,
                                                    UseAllAutoDetection, url));
   }
@@ -67,7 +68,7 @@ class CORE_EXPORT TextResourceDecoder {
   // https://encoding.spec.whatwg.org/#utf-8-decode.
   static std::unique_ptr<TextResourceDecoder> createAlwaysUseUTF8ForText() {
     return WTF::wrapUnique(new TextResourceDecoder(
-        "plain/text", UTF8Encoding(), AlwaysUseUTF8ForText, String()));
+        "plain/text", UTF8Encoding(), AlwaysUseUTF8ForText, KURL()));
   }
   ~TextResourceDecoder();
 
@@ -113,7 +114,7 @@ class CORE_EXPORT TextResourceDecoder {
   TextResourceDecoder(const String& mimeType,
                       const WTF::TextEncoding& defaultEncoding,
                       EncodingDetectionOption,
-                      const String& url);
+                      const KURL& hintUrl);
 
  private:
   enum ContentType {
@@ -137,7 +138,7 @@ class CORE_EXPORT TextResourceDecoder {
   std::unique_ptr<TextCodec> m_codec;
   EncodingSource m_source;
   const char* m_hintEncoding;
-  const CString m_hintUrl;
+  const KURL& m_hintUrl;

[tkent, 2017/03/31 00:47:30]

This should be |const KURL|, not |const KURL&|. The current code holds a
reference to a temporary object.

[Jinsuk Kim, 2017/03/31 01:33:29]

Oops. You're correct. Then we have to create a new KURL instance for every
TextResourceDecoder... In fact this is worse because previously only those TRDs
that do auto encoding detection create one (auto detection is called just once
per TRD). Do you think it's still worth landing this CL, even if
TextResourceDecoder instantiates a new KURL? It was the whole point of this CL
from my POV.

One thing I'd suggest is: given that such problem happens mostly for tests only,
how about define a a static immutable null KURL instance and pass it instead of
a temporary object here?

If you believe this CL still has value even if every TextResourceDecoder
instantiates a new KURL, I'll go ahead and land it after changing the type to
|const KURL|.

[tkent, 2017/03/31 08:12:24]

I think this CL is still worth to land.  Copying cost of KRUL isn't large, and
the code becomes cleaner.

[Jinsuk Kim, 2017/04/02 22:46:10]

Done.

   Vector<char> m_buffer;
   char m_hintLanguage[3];
   bool m_checkedForBOM;