[py] Deprecate use of AppCache APIs

Cr-Mirrored-From: https://chromium.googlesource.com/external/github.com/SeleniumHQ/selenium
Cr-Mirrored-Commit: 30542f541a5ec8c5049f5c8c4e65c99a4c3baf57
diff --git a/selenium/webdriver/common/html5/application_cache.py b/selenium/webdriver/common/html5/application_cache.py
index 7487274..520d4b3 100644
--- a/selenium/webdriver/common/html5/application_cache.py
+++ b/selenium/webdriver/common/html5/application_cache.py
@@ -19,6 +19,9 @@
 The ApplicationCache implementation.
 """
 
+
+import warnings
+
 from selenium.webdriver.remote.command import Command
 
 
@@ -38,6 +41,8 @@
         :Args:
          - driver: The WebDriver instance which performs user actions.
         """
+        warnings.warn("Application Cache is being removed from all major browsers. This feature will be removed in future versions",
+                      DeprecationWarning, stacklevel=2)
         self.driver = driver
 
     @property