Supervised user interstitial: Handle missing custodian profile URL.

chrome/browser/supervised_user/supervised_user_interstitial.cc

Index: chrome/browser/supervised_user/supervised_user_interstitial.cc
diff --git a/chrome/browser/supervised_user/supervised_user_interstitial.cc b/chrome/browser/supervised_user/supervised_user_interstitial.cc
index 17baddf27f49f5c33791d9819eb1f5b871b4df8a..f561c45f3bd67483854b964529c468308c9723d8 100644
--- a/chrome/browser/supervised_user/supervised_user_interstitial.cc
+++ b/chrome/browser/supervised_user/supervised_user_interstitial.cc
@@ -148,26 +148,32 @@ std::string SupervisedUserInterstitial::GetHTMLContents() {
   bool allow_access_requests = supervised_user_service->AccessRequestsEnabled();
   strings.SetBoolean("allowAccessRequests", allow_access_requests);
 
-  GURL profile_url = GURL(profile->GetPrefs()->GetString(
+  GURL base_url = GURL(profile->GetPrefs()->GetString(
       prefs::kSupervisedUserCustodianProfileURL));
+  if (!base_url.is_valid())
+    base_url = GURL("https://dummy.url");
+  DCHECK(base_url.is_valid());
   std::string profile_image_url = profile->GetPrefs()->GetString(
       prefs::kSupervisedUserCustodianProfileImageURL);
   strings.SetString("avatarURL1x", BuildAvatarImageUrl(profile_image_url,
-                                                       profile_url,
+                                                       base_url,
                                                        kAvatarSize1x));
   strings.SetString("avatarURL2x", BuildAvatarImageUrl(profile_image_url,
-                                                       profile_url,
+                                                       base_url,
                                                        kAvatarSize2x));
 
-  GURL profile_url2 = GURL(profile->GetPrefs()->GetString(
+  GURL base_url2 = GURL(profile->GetPrefs()->GetString(
       prefs::kSupervisedUserSecondCustodianProfileURL));
+  if (!base_url2.is_valid())
+    base_url2 = GURL("https://dummy.url");
+  DCHECK(base_url2.is_valid());
   std::string profile_image_url2 = profile->GetPrefs()->GetString(
       prefs::kSupervisedUserSecondCustodianProfileImageURL);
   strings.SetString("secondAvatarURL1x", BuildAvatarImageUrl(profile_image_url2,
-                                                             profile_url2,
+                                                             base_url2,
                                                              kAvatarSize1x));
   strings.SetString("secondAvatarURL2x", BuildAvatarImageUrl(profile_image_url2,
-                                                             profile_url2,
+                                                             base_url2,
                                                              kAvatarSize2x));
 
   base::string16 custodian =