GitLab

Move ScopedAccessibilityFocus from ui/views/cocoa to ui/base/cocoa,
because it is going to be used by content/ (which, for the moment,
does not depends on ui/views, though I would like to add an explicit
dependency at some point).

Rename ScopedAccessibilityFocus to AccessibilityFocusOverrider, and
- make it track
  - whether or not the view it represents if the first responder for
    its window
  - whether or not its window is key
- override -[NSApplication accessibilityFocusedUIElement] only when
  both of those conditions are true

Apply this scheme to the two main NSViews
- BridgedContentView uses an AccessibilityFocusOverrider in
  BridgedNativeWidgetHostImpl
- RenderWidgetHostViewCocoa uses an AccessibilityFocusOverrider in
  RenderWidgetHostViewMac

Change slightly the way that NSWindow key status is tracked between
RenderWidgetHostViewCocoa/Mac.
- These changes were only send to the browser when the view was also
  first responder
- Change this to always send changes in key status, and early-out
  when the view is not first responder on the browser side.

Bug: 900846
Change-Id: I15bb144ae4570eeffa51c4609f58aa8b58b892d9
Reviewed-on: https://chromium-review.googlesource.com/c/1345121Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: ccameron <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610209}