Add --use-more-webui runtime flag to toggle WebUI replacements for native dialogs.

chrome/browser/ui/webui/chrome_web_ui.cc

Index: chrome/browser/ui/webui/chrome_web_ui.cc
diff --git a/chrome/browser/ui/webui/chrome_web_ui.cc b/chrome/browser/ui/webui/chrome_web_ui.cc
index 885711ce9fd6feee87c9969a998da0b585fbcf4e..cd9b0ee519324f2e3b624d8055b3f053fe1f2a5b 100644
--- a/chrome/browser/ui/webui/chrome_web_ui.cc
+++ b/chrome/browser/ui/webui/chrome_web_ui.cc
@@ -4,9 +4,15 @@
 
 #include "chrome/browser/ui/webui/chrome_web_ui.h"
 
+#include "base/command_line.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/common/chrome_switches.h"
 #include "content/browser/tab_contents/tab_contents.h"
 
+#if defined(TOOLKIT_VIEWS)
+#include "views/widget/widget.h"
+#endif
+
 ChromeWebUI::ChromeWebUI(TabContents* contents)
     : WebUI(contents),
       force_bookmark_bar_visible_(false) {
@@ -18,3 +24,13 @@ ChromeWebUI::~ChromeWebUI() {
 Profile* ChromeWebUI::GetProfile() const {
   return Profile::FromBrowserContext(tab_contents()->browser_context());
 }
+
+// static
+bool ChromeWebUI::IsMoreWebUI() {
+  bool more_webui = CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kUseMoreWebUI);
+#if defined(TOOLKIT_VIEWS)
+  more_webui |= views::Widget::IsPureViews();
+#endif
+  return more_webui;
+}