Do not fire a focus event on the document object when the document itself is not focused

Removes some legacy behavior that is not present in Firefox.
The busy state is not being used on the document object so checking for its presence is unnecessary.

R=dmazzoni@chromium.org, aleventhal@chromium.org

Bug: 897177
Change-Id: I766b0fb9c862b76803a43c38c34fd62b30336f5f
Reviewed-on: https://chromium-review.googlesource.com/c/1294303Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601753}

content/browser/accessibility/browser_accessibility_manager_win.cc

@@ -84,13 +84,6 @@ void BrowserAccessibilityManagerWin::FireFocusEvent(
     BrowserAccessibility* node) {
   BrowserAccessibilityManager::FireFocusEvent(node);
   DCHECK(node);
-  // On Windows, we always fire a FOCUS event on the root of a frame before
-  // firing a focus event within that frame.
-  if (node->manager() != last_focused_manager_ &&
-      node != node->manager()->GetRoot()) {
-    FireWinAccessibilityEvent(EVENT_OBJECT_FOCUS, node->manager()->GetRoot());
-  }
-
   FireWinAccessibilityEvent(EVENT_OBJECT_FOCUS, node);
 }