disable-battery-status-updater.patch

From: Joachim Bauch <jojo@struktur.de>
Date: Tue, 4 Aug 2015 15:15:53 +0200
Subject: disable battery status updater

The W3C Battery Status API[1] has quite a laughable statement:

"The information disclosed has minimal impact on privacy or
fingerprinting, and therefore is exposed without permission grants".

Along comes a paper "The leaking battery, A privacy analysis of the
HTML5 Battery Status API."

Clean up after the W3C and disable the battery status updater which
could be used to identity users[2].

[1] http://www.w3.org/TR/battery-status/
[2] https://eprint.iacr.org/2015/616.pdf

References: https://github.com/iridium-browser/iridium-browser/issues/40

License: GPL-3.0-only - https://spdx.org/licenses/GPL-3.0-only.html
---
 services/device/battery/battery_status_service.cc | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/services/device/battery/battery_status_service.cc b/services/device/battery/battery_status_service.cc
--- a/services/device/battery/battery_status_service.cc
+++ b/services/device/battery/battery_status_service.cc
@@ -43,17 +43,7 @@ base::CallbackListSubscription BatteryStatusService::AddCallback(
   if (!battery_fetcher_)
     battery_fetcher_ = BatteryStatusManager::Create(update_callback_);
 
-  if (callback_list_.empty()) {
-    bool success = battery_fetcher_->StartListeningBatteryChange();
-    // On failure pass the default values back.
-    if (!success)
-      callback.Run(mojom::BatteryStatus());
-  }
-
-  if (status_updated_) {
-    // Send recent status to the new callback if already available.
-    callback.Run(status_);
-  }
+  callback.Run(mojom::BatteryStatus());
 
   return callback_list_.Add(callback);
 }
--