Revert "Reland "Move a bunch of ChromeOS APIs out of chrome/browser/extensions."""

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 43f90aefbc3a4871693218808cd139085c6609f3..b3a4936471fa7c497eef35c4505b36e944416d4b 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -308,13 +308,18 @@
           'enable_flapper_hacks%': 0,
         }],
 
-        # Enable file manager extension on Chrome OS.
-        ['chromeos==1', {
+        # Enable file manager extension on Chrome OS or Aura.
+        ['chromeos==1 or use_aura==1', {
           'file_manager_extension%': 1,
         }, {
           'file_manager_extension%': 0,
         }],
 
+        # ... except on Windows even with Aura.
+        ['use_aura==1 and OS=="win"', {
+          'file_manager_extension%': 0,
+        }],
+
         # Enable WebUI TaskManager always on Chrome OS or Aura.
         ['chromeos==1 or use_aura==1', {
           'webui_task_manager%': 1,