Add chrome://popular-sites-internals/ to iOS.

ios/chrome/browser/chrome_url_constants.h

Index: ios/chrome/browser/chrome_url_constants.h
diff --git a/ios/chrome/browser/chrome_url_constants.h b/ios/chrome/browser/chrome_url_constants.h
index 3960571011974093670be80e2ed731b37a3a5592..b678cbd0f3bd2820133e2f97f427043da94a8235 100644
--- a/ios/chrome/browser/chrome_url_constants.h
+++ b/ios/chrome/browser/chrome_url_constants.h
@@ -28,6 +28,7 @@ extern const char kChromeUIFlagsURL[];
 extern const char kChromeUIHistoryURL[];
 extern const char kChromeUINewTabURL[];
 extern const char kChromeUIPhysicalWebURL[];
+extern const char kChromeUIPopularSitesInternalsURL[];
 extern const char kChromeUISettingsURL[];
 extern const char kChromeUITermsURL[];
 extern const char kChromeUIVersionURL[];
@@ -49,6 +50,7 @@ extern const char kChromeUINetExportHost[];
 extern const char kChromeUINewTabHost[];
 extern const char kChromeUIOmahaHost[];
 extern const char kChromeUIPhysicalWebHost[];
+extern const char kChromeUIPopularSitesInternalsHost[];
 extern const char kChromeUIPolicyHost[];
 extern const char kChromeUISignInInternalsHost[];
 extern const char kChromeUISyncInternalsHost[];