Allow keyboard shortcuts can be captured by webpage when toolbar is not visible

chrome/browser/ui/cocoa/browser_window_cocoa.mm

Index: chrome/browser/ui/cocoa/browser_window_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/browser_window_cocoa.mm b/chrome/browser/ui/cocoa/browser_window_cocoa.mm
index 2991e80ab6535094deb95aa54984a6c72c13f3b9..d10a2e40c7d565f05ad1c8f51f632f77c499e19f 100644
--- a/chrome/browser/ui/cocoa/browser_window_cocoa.mm
+++ b/chrome/browser/ui/cocoa/browser_window_cocoa.mm
@@ -322,6 +322,16 @@ NSString* BrowserWindowCocoa::WindowTitle() {
       browser_->GetWindowTitleForCurrentTab(include_app_name));
 }
 
+bool BrowserWindowCocoa::IsToolbarShowing() const {
+  if (!IsFullscreen()) {
+    return true;
+  }
+
+  // TODO(zijiehe): Retrieve the visibility of toolbar from

[msw, 2017/04/04 19:32:48]

Is this okay to leave as a TODO? It seems like that's why this was reverted
previously? Please seek reviewers for this aspect of the change before seeking
owners review.

[Hzj_jie, 2017/04/04 20:54:43]

As long as this function returns true, the behavior should keep unchanged.
I have not received my Mac workstation yet. So unfortunately I cannot implement
it blindly now.

+  // FullscreenToolbarController.
+  return true;
+}
+
 void BrowserWindowCocoa::BookmarkBarStateChanged(
     BookmarkBar::AnimateChangeType change_type) {
   [[controller_ bookmarkBarController]