Simplify "WouldTaintOrigin" concept in media/blink

Currently WebMediaPlayer has three predicates:
 - DidGetOpaqueResponseFromServiceWorker
 - HasSingleSecurityOrigin
 - DidPassCORSAccessCheck
. These are used to determine whether the response body is available
for scripts. They are known to be confusing, and actually
MediaElementAudioSourceHandler::WouldTaintOrigin misuses them.

This CL merges the three predicates to one, WouldTaintOrigin, to remove
the confusion. Now the "response type" concept is available and we
don't need a custom CORS check, so this CL removes
BaseAudioContext::WouldTaintOrigin. This CL also renames
URLData::has_opaque_data_ and its (direct and indirect) data accessors
to match the spec.

Bug: 849942, 875153
Change-Id: I6acf50169d7445c4ff614e80ac606f79ee577d2a
Reviewed-on: https://chromium-review.googlesource.com/c/1238098
Reviewed-by: Fredrik Hubinette <hubbe@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Raymond Toy <rtoy@chromium.org>
Commit-Queue: Yutaka Hirano <yhirano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#598258}
void WebMediaPlayerImpl::DisableOverlay() {
  overlay_enabled_ = false;
  if (overlay_mode_ == OverlayMode::kUseContentVideoView) {
    surface_created_cb_.Cancel();
  } else if (overlay_mode_ == OverlayMode::kUseAndroidOverlay) {
    token_available_cb_.Cancel();
    overlay_routing_token_is_pending_ = false;
    overlay_routing_token_ = OverlayInfo::RoutingToken();
  }

  if (decoder_requires_restart_for_overlay_)
    ScheduleRestart();
  else
    MaybeSendOverlayInfoToDecoder();
}

void WebMediaPlayerImpl::DisableOverlay() {
  overlay_enabled_ = false;
  if (overlay_mode_ == OverlayMode::kUseContentVideoView) {
    surface_created_cb_.Cancel();
  } else if (overlay_mode_ == OverlayMode::kUseAndroidOverlay) {
    token_available_cb_.Cancel();
    overlay_routing_token_is_pending_ = false;
    overlay_routing_token_ = OverlayInfo::RoutingToken();
  }

  if (decoder_requires_restart_for_overlay_)
    ScheduleRestart();
  else
    MaybeSendOverlayInfoToDecoder();
}
