Disable navigations in the unload handler.

third_party/WebKit/Source/core/frame/Deprecation.cpp

Index: third_party/WebKit/Source/core/frame/Deprecation.cpp
diff --git a/third_party/WebKit/Source/core/frame/Deprecation.cpp b/third_party/WebKit/Source/core/frame/Deprecation.cpp
index 403de9e6c787cc4e75540122f565fbc32c27134d..0f379f26727569d56c1708b2f0a38910b449849f 100644
--- a/third_party/WebKit/Source/core/frame/Deprecation.cpp
+++ b/third_party/WebKit/Source/core/frame/Deprecation.cpp
@@ -373,9 +373,6 @@ String Deprecation::deprecationMessage(UseCounter::Feature feature)
     case UseCounter::UntrustedEventDefaultHandled:
         return String::format("A DOM event generated from JavaScript has triggered a default action inside the browser. This behavior is non-standard and will be removed in %s. See https://www.chromestatus.com/features/5718803933560832 for more details.", milestoneString(53));
 
-    case UseCounter::UnloadHandler_Navigation:
-        return "Navigating in the unload handler is deprecated and will be removed.";
-
     case UseCounter::TouchStartUserGestureUtilized:
         return willBeRemoved("Performing operations that require explicit user interaction on touchstart events", 54, "5649871251963904");