Replace "http" etc with the url_constants version. This was a previous TODO for webplugin_proxy....

content/plugin/webplugin_proxy.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/plugin/webplugin_proxy.h"
 
 #include "build/build_config.h"
 
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_handle.h"
 #include "base/shared_memory.h"
 #include "build/build_config.h"
 #include "content/common/content_client.h"
 #include "content/common/plugin_messages.h"
+#include "content/common/url_constants.h"
 #include "content/plugin/npobject_proxy.h"
 #include "content/plugin/npobject_util.h"
 #include "content/plugin/plugin_channel.h"
 #include "content/plugin/plugin_thread.h"
 #include "skia/ext/platform_device.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebBindings.h"
 #include "ui/gfx/blit.h"
 #include "ui/gfx/canvas.h"
 #include "webkit/plugins/npapi/webplugin_delegate_impl.h"
 
@@ skipping 257 matching lines @@
                                       int notify_id,
                                       bool popups_allowed,
                                       bool notify_redirects) {
  if (!target && (0 == base::strcasecmp(method, "GET"))) {
     // Please refer to https://bugzilla.mozilla.org/show_bug.cgi?id=366082
     // for more details on this.
     if (delegate_->GetQuirks() &
         webkit::npapi::WebPluginDelegateImpl::
             PLUGIN_QUIRK_BLOCK_NONSTANDARD_GETURL_REQUESTS) {
       GURL request_url(url);
-      if (!request_url.SchemeIs("http") &&
-          !request_url.SchemeIs("https") &&
-          !request_url.SchemeIs("ftp")) {
+      if (!request_url.SchemeIs(chrome::kHttpScheme) &&
+          !request_url.SchemeIs(chrome::kHttpsScheme) &&
+          !request_url.SchemeIs(chrome::kFtpScheme)) {
         return;
       }
     }
   }
 
   PluginHostMsg_URLRequest_Params params;
   params.url = url;
   params.method = method;
   if (target)
     params.target = std::string(target);
@@ skipping 342 matching lines @@
       resource_clients_.erase(index++);
     } else {
       index++;
     }
   }
 }
 
 void WebPluginProxy::URLRedirectResponse(bool allow, int resource_id) {
   Send(new PluginHostMsg_URLRedirectResponse(route_id_, allow, resource_id));
 }