XHR: Lowercase header names returned by getAllResponseHeaders().

third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp

Index: third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
diff --git a/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp b/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
index 561ff2d1b3e11519e87a69fe8e8d949800db63aa..a374123cd961c671e4f80638c420665799fab11e 100644
--- a/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
+++ b/third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequest.cpp
@@ -1402,7 +1402,7 @@ String XMLHttpRequest::getAllResponseHeaders() const {
         !access_control_expose_header_set.Contains(it->key))
       continue;
 
-    string_builder.Append(it->key);
+    string_builder.Append(it->key.LowerASCII());
     string_builder.Append(':');
     string_builder.Append(' ');
     string_builder.Append(it->value);