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

chrome/browser/ui/browser_window.h

Index: chrome/browser/ui/browser_window.h
diff --git a/chrome/browser/ui/browser_window.h b/chrome/browser/ui/browser_window.h
index 25ded9161b5470971f8520c6f4d309c15f777d7d..ce6c27349cc86f6582d81ad22bbeac99b6cd03d6 100644
--- a/chrome/browser/ui/browser_window.h
+++ b/chrome/browser/ui/browser_window.h
@@ -220,9 +220,15 @@ class BrowserWindow : public ui::BaseWindow {
   // Returns whether the tab strip is editable (for extensions).
   virtual bool IsTabStripEditable() const = 0;
 
-  // Returns whether the tool bar is visible or not.
+  // Returns whether the toolbar is accessible or not. It's called "Visible()"

[msw, 2017/04/04 22:46:39]

Rename this function something more representative of the toolbar's state or
return an enum like ToolbarVisibility { VISIBLE, HIDDEN, AUTOHIDE_HIDDEN,
AUTOHIDE_REVEALED } (perhaps something like this exists or there are better
existing names for this behavior/state). If you just rename this function,
'Accessible' is not a great name, evokes thoughts about a11y, maybe
IsToolbarAvailable or IsToolbarPresent (or something better...). At the very
least, add a TODO to rename and revise the comment to something like "Returns
whether the toolbar is potentially visible. This function may return true even
if the toolbar is temporarily hidden, but generally available to the user (ie.
revealed when the cursor hovers the top of the screen)." You can optionally look
at the similar ash shelf auto-hide behavior/state code (but that's admittedly
not an optimal design).

[Hzj_jie, 2017/04/05 18:09:17]

I used to rename it to IsToolbarAvailable(), which is a very reasonable name
IMO. But I found some other functions, such as IsTabStripVisible(), which are
also called "Visible", even they are returning "Available". So I doubt whether
this is a naming convention.
Returning an enum increases the complexity to the users, which, I believe, will
become a huge change. I am happy to add a TODO here to state the plan of
renaming these functions. But I definitely do not want to do it in this change
:)

+  // to follow the name convention. But it does not indicate the visibility of
+  // the toolbar, i.e. toolbar may be hidden, and only visible when the mouse
+  // cursor is at a certain place.
   virtual bool IsToolbarVisible() const = 0;
 
+  // Returns whether the toolbar is showing up on the screen.
+  virtual bool IsToolbarShowing() const = 0;
+
   // Shows the Update Recommended dialog box.
   virtual void ShowUpdateChromeDialog() = 0;