Add a basic stub Polymer settings page at chrome://md-settings.

chrome/common/url_constants.cc

Index: chrome/common/url_constants.cc
diff --git a/chrome/common/url_constants.cc b/chrome/common/url_constants.cc
index 9487e8ccb12d0d5f7363c40fed0d1856174ed97f..a3aedca429a20baf70c7ebb7a48697f49906170c 100644
--- a/chrome/common/url_constants.cc
+++ b/chrome/common/url_constants.cc
@@ -58,6 +58,7 @@ const char kChromeUIInspectURL[] = "chrome://inspect/";
 const char kChromeUIInstantURL[] = "chrome://instant/";
 const char kChromeUIInterstitialURL[] = "chrome://interstitials/";
 const char kChromeUIInvalidationsURL[] = "chrome://invalidations/";
+const char kChromeUIMdSettingsURL[] = "chrome://md-settings/";
 const char kChromeUIMemoryRedirectURL[] = "chrome://memory-redirect/";
 const char kChromeUIMemoryURL[] = "chrome://memory/";
 const char kChromeUIMetroFlowURL[] = "chrome://make-metro/";
@@ -200,6 +201,7 @@ const char kChromeUIInterstitialHost[] = "interstitials";
 const char kChromeUIInvalidationsHost[] = "invalidations";
 const char kChromeUIKillHost[] = "kill";
 const char kChromeUILocalStateHost[] = "local-state";
+const char kChromeUIMdSettingsHost[] = "md-settings";
 const char kChromeUIMemoryHost[] = "memory";
 const char kChromeUIMemoryInternalsHost[] = "memory-internals";
 const char kChromeUIMemoryRedirectHost[] = "memory-redirect";