Bug 1454325 - update XHR upload content-type handling to match the spec. r=baku

update XHR upload content-type handling to match the spec

Differential Revision: https://phabricator.services.mozilla.com/D23251

--HG--
extra : moz-landing-system : lando

dom/xhr/XMLHttpRequestMainThread.cpp

@@ -2776,16 +2776,19 @@ nsresult XMLHttpRequestMainThread::SendInternal(const BodyExtractorBase* aBody,
         uploadContentType = defaultContentType;
       } else if (aBodyIsDocumentOrString &&
                  StaticPrefs::dom_xhr_standard_content_type_normalization()) {
-        UniquePtr<CMimeType> parsed = CMimeType::Parse(uploadContentType);
-        if (parsed && parsed->HasParameter(kLiteralString_charset)) {
-          parsed->SetParameterValue(kLiteralString_charset,
-                                    kLiteralString_UTF_8);
-          parsed->Serialize(uploadContentType);
+        UniquePtr<CMimeType> contentTypeRecord =
+            CMimeType::Parse(uploadContentType);
+        nsAutoCString charset;
+        if (contentTypeRecord &&
+            contentTypeRecord->GetParameterValue(kLiteralString_charset,
+                                                 charset) &&
+            !charset.EqualsIgnoreCase("utf-8")) {
+          contentTypeRecord->SetParameterValue(kLiteralString_charset,
+                                               kLiteralString_UTF_8);
+          contentTypeRecord->Serialize(uploadContentType);
         }
-      }
-
-      // We don't want to set a charset for streams.
-      if (!charset.IsEmpty()) {
+      } else if (!charset.IsEmpty()) {
+        // We don't want to set a charset for streams.
         // Replace all case-insensitive matches of the charset in the
         // content-type with the correct case.
         RequestHeaders::CharsetIterator iter(uploadContentType);

modules/libpref/init/StaticPrefList.h

@@ -483,11 +483,10 @@ VARCACHE_PREF(
 )
 
 // Enable content type normalization of XHR uploads via MIME Sniffing standard
-// Disabled for now in bz1499136
 VARCACHE_PREF(
   "dom.xhr.standard_content_type_normalization",
    dom_xhr_standard_content_type_normalization,
-  RelaxedAtomicBool, false
+  RelaxedAtomicBool, true
 )
 
 // Block multiple external protocol URLs in iframes per single event.

testing/web-platform/meta/xhr/send-content-type-charset.htm.ini

@@ -1,19 +0,0 @@
-[send-content-type-charset.htm]
-  [charset with space that is UTF-8 does not change]
-    expected: FAIL
-
-  [charset in double quotes with backslashes that is UTF-8 does not change]
-    expected: FAIL
-
-  [If charset= param is UTF-8 (case-insensitive), it should not be changed (bogus charset)]
-    expected: FAIL
-
-  [If charset= param is UTF-8 (case-insensitive), it should not be changed]
-    expected: FAIL
-
-  [charset in double quotes that is UTF-8 does not change]
-    expected: FAIL
-
-  [charset with trailing space that is UTF-8 does not change]
-    expected: FAIL
-