Disable back button when stack is empty

chrome/browser/android/vr_shell/ui_elements/url_bar.cc

Index: chrome/browser/android/vr_shell/ui_elements/url_bar.cc
diff --git a/chrome/browser/android/vr_shell/ui_elements/url_bar.cc b/chrome/browser/android/vr_shell/ui_elements/url_bar.cc
index 1cd156a010994ad421f95fa6d457634254f80b22..23ec9339470db7d8b2c3c3293aada55b512ed338 100644
--- a/chrome/browser/android/vr_shell/ui_elements/url_bar.cc
+++ b/chrome/browser/android/vr_shell/ui_elements/url_bar.cc
@@ -83,6 +83,10 @@ void UrlBar::SetURL(const GURL& gurl) {
   texture_->SetURL(gurl);
 }
 
+void UrlBar::SetHistoryButtonsEnabled(bool can_go_back, bool can_go_forward) {

[cjgrant, 2017/05/29 16:12:25]

URL bar presumably also doesn't care about forward.

[ymalik, 2017/05/29 17:34:10]

Done.

+  texture_->SetHistoryButtonsEnabled(can_go_back, can_go_forward);
+}
+
 void UrlBar::SetSecurityLevel(security_state::SecurityLevel level) {
   texture_->SetSecurityLevel(level);
 }