Update to Chromium version 82.0.4085.0 (#749737)

- Building on macOS now requires the 10.15 SDK. Xcode 11.3 is recommended as
  Xcode 11.4 is not currently supported (see https://crbug.com/1065146).
- Jumbo build configuration is no longer supported.

Chromium is skipping the M82 release and consequently no CEF 4085 branch will
be created. For details on the Chromium decision see
https://groups.google.com/a/chromium.org/d/msg/chromium-dev/Vn7uzglqLz0/JItlSrZxBAAJ

libcef/browser/browser_context.cc

@@ -48,7 +48,6 @@
 #include "extensions/browser/process_manager.h"
 #include "extensions/common/constants.h"
 #include "net/proxy_resolution/proxy_config_service.h"
-#include "net/proxy_resolution/proxy_resolution_service.h"
 #include "services/network/public/mojom/cors_origin_pattern.mojom.h"
 
 using content::BrowserThread;