Support for json media types as (non-image) mime types.

Source/core/dom/DOMImplementation.cpp

Index: Source/core/dom/DOMImplementation.cpp
diff --git a/Source/core/dom/DOMImplementation.cpp b/Source/core/dom/DOMImplementation.cpp
index 83885b3bf10f9d2f46ba4d3d4526b052b8891ba8..14f2aba014b86eb8a9840ac55cb1a9afe5dcb209 100644
--- a/Source/core/dom/DOMImplementation.cpp
+++ b/Source/core/dom/DOMImplementation.cpp
@@ -294,17 +294,47 @@ bool DOMImplementation::isXMLMIMEType(const String& mimeType)
     return true;
 }
 
+static bool isJSONType(const String& mimeType)
+{
+    if (mimeType.startsWith("application/json", false))
+        return true;
+    if (mimeType.startsWith("application/", false)) {
+        size_t subtype = mimeType.find("+json", 12, false);
+        if (subtype != kNotFound) {
+            // Just check that a parameter wasn't matched.
+            size_t parameterMarker = mimeType.find(";");
+            return (parameterMarker == kNotFound || parameterMarker > subtype);
+        }
+    }
+    return false;
+}
+
+static bool isTextPlainType(const String& mimeType)
+{
+    return (mimeType.startsWith("text/", false)
+        && !(equalIgnoringCase(mimeType, "text/html")
+            || equalIgnoringCase(mimeType, "text/xml")
+            || equalIgnoringCase(mimeType, "text/xsl")));
+}
+
 bool DOMImplementation::isTextMIMEType(const String& mimeType)
 {
-    if (MIMETypeRegistry::isSupportedJavaScriptMIMEType(mimeType)
-        || mimeType == "application/json" // Render JSON as text/plain.
-        || (mimeType.startsWith("text/") && mimeType != "text/html"
-            && mimeType != "text/xml" && mimeType != "text/xsl"))
+    if (MIMETypeRegistry::isSupportedJavaScriptMIMEType(mimeType) || isJSONType(mimeType) || isTextPlainType(mimeType))
         return true;
 
     return false;
 }
 
+const char* DOMImplementation::getTextDefaultEncodingName(const String& mimeType)
+{
+    ASSERT(isTextMIMEType(mimeType));
+    if (MIMETypeRegistry::isSupportedJavaScriptMIMEType(mimeType) || isJSONType(mimeType))
+        return "UTF-8";
+
+    // The HTTP/1.1 default.
+    return "ISO-8859-1";
+}
+
 PassRefPtr<HTMLDocument> DOMImplementation::createHTMLDocument(const String& title)
 {
     DocumentInit init = DocumentInit::fromContext(m_document.contextDocument())