Use in-class initializers for base::WeakPtrFactory in components/.

Generated by: https://chromium-review.googlesource.com/c/chromium/src/+/1689216

Bug: 981415
Change-Id: I706ec55f1f533ef616f400791d69a51e9a151da1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1699508
Commit-Queue: Jeremy Roman <[email protected]>
Reviewed-by: Colin Blundell <[email protected]>
Cr-Commit-Position: refs/heads/master@{#677340}
diff --git a/components/zoom/zoom_event_manager.cc b/components/zoom/zoom_event_manager.cc
index 39a4c63c..fdb3a60 100644
--- a/components/zoom/zoom_event_manager.cc
+++ b/components/zoom/zoom_event_manager.cc
@@ -25,7 +25,7 @@
       context->GetUserData(kBrowserZoomEventManager));
 }
 
-ZoomEventManager::ZoomEventManager() : weak_ptr_factory_(this) {}
+ZoomEventManager::ZoomEventManager() {}
 
 ZoomEventManager::~ZoomEventManager() {}