Simplify the user agent code some more since after r255534 it's not affected by the site's URL.

content/test/test_webkit_platform_support.cc

Index: content/test/test_webkit_platform_support.cc
===================================================================
--- content/test/test_webkit_platform_support.cc	(revision 255867)
+++ content/test/test_webkit_platform_support.cc	(working copy)
@@ -126,6 +126,15 @@
       BlinkPlatformImpl::createURLLoader());
 }
 
+blink::WebString TestWebKitPlatformSupport::userAgent() {
+  return blink::WebString::fromUTF8("DumpRenderTree/0.0.0.0");
+}
+
+blink::WebString TestWebKitPlatformSupport::userAgent(
+    const blink::WebURL& url) {
+  return userAgent();
+}
+
 blink::WebData TestWebKitPlatformSupport::loadResource(const char* name) {
   if (!strcmp(name, "deleteButton")) {
     // Create a red 30x30 square.