Make options zoom isolated, match embedder zoom on navigation.

components/ui/zoom/zoom_controller.cc

Index: components/ui/zoom/zoom_controller.cc
diff --git a/components/ui/zoom/zoom_controller.cc b/components/ui/zoom/zoom_controller.cc
index 964d20f7cff99b45c1eec0fb7bee5cb0174c4fdc..a56aaa98339da6f16503c658bcd5716b9208e2a6 100644
--- a/components/ui/zoom/zoom_controller.cc
+++ b/components/ui/zoom/zoom_controller.cc
@@ -135,6 +135,9 @@ bool ZoomController::SetZoomLevelByClient(
   } else {
     if (!entry) {
       last_client_ = NULL;
+      // If we exit without triggering an update, we should clear event_data_,
+      // else we may later trigger a DCHECK(event_data_).
+      event_data_.reset();
       return false;
     }
     std::string host =