If JavaScript shows a dialog, cause the page to lose fullscreen.

BUG=670135, 550017, 726761, 728276

Review-Url: https://codereview.chromium.org/2906133004
Cr-Commit-Position: refs/heads/master@{#478884}
void UpdateAccessibilityModeOnFrame(RenderFrameHost* frame_host) {
  static_cast<RenderFrameHostImpl*>(frame_host)->UpdateAccessibilityMode();
}

void UpdateAccessibilityModeOnFrame(RenderFrameHost* frame_host) {
  static_cast<RenderFrameHostImpl*>(frame_host)->UpdateAccessibilityMode();
}
