Ensure proxy safety on Android
Mike mentions in #21625 (moved):
Android stuff that definitely leaks that we should fix (missing proxy params to HttpUrlConnection - these need to use the buildHttpConnection helper to get a proxy):
* mobile/android/base/java/org/mozilla/gecko/feeds/FeedFetcher.java
* mobile/android/base/java/org/mozilla/gecko/media/GeckoMediaDrmBridgeV21.java
* mobile/android/base/java/org/mozilla/gecko/search/SearchEngineManager.java
* mobile/android/thirdparty/com/keepsafe/switchboard/SwitchBoard.java
Blocker of releasing TBA.