Make it possible to set the display mode from Chromium

content/shell/browser/shell.cc

Index: content/shell/browser/shell.cc
diff --git a/content/shell/browser/shell.cc b/content/shell/browser/shell.cc
index 209d4c30e003c4a6d4022bf41f29cd785642d8ba..18ff879bdbbb51db2fa28d7e4a42f24495faabc5 100644
--- a/content/shell/browser/shell.cc
+++ b/content/shell/browser/shell.cc
@@ -313,6 +313,15 @@ bool Shell::IsFullscreenForTabOrPending(const WebContents* web_contents) const {
 #endif
 }
 
+blink::WebDisplayMode Shell::GetDisplayMode(
+    const WebContents* web_contents) const {
+ // TODO : should return blink::WebDisplayModeFullscreen wherever user puts
+ // a browser window into fullscreen (not only in case of renderer-initiated
+ // fullscreen mode): crbug.com/476874.
+ return IsFullscreenForTabOrPending(web_contents) ?
+     blink::WebDisplayModeFullscreen : blink::WebDisplayModeBrowser;
+}
+
 void Shell::RequestToLockMouse(WebContents* web_contents,
                                bool user_gesture,
                                bool last_unlocked_by_target) {