Turn off requirement that cross-origin top navigation be accompanied by a user gesture.

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

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Simon Hausmann <hausmann@kde.org>
  *                     2000 Stefan Schimanski <1Stein@gmx.de>
  *                     2001 George Staikos <staikos@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2005 Alexey Proskuryakov <ap@nypop.com>
@@ skipping 164 matching lines @@
     UseCounter::count(&targetFrame, UseCounter::TopNavigationFromSubFrame);
     bool hasUserGesture =
         isLocalFrame()
             ? toLocalFrame(this)->document()->hasReceivedUserGesture()
             : false;
     if (hasUserGesture)
       framebustParams |= userGestureBit;
     if (isAllowedNavigation)
       framebustParams |= allowedBit;
     framebustHistogram.count(framebustParams);
-    // Frame-busting used to be generally allowed in most situations, but may
-    // now blocked if there is no user gesture.
-    if (!RuntimeEnabledFeatures::
-            framebustingNeedsSameOriginOrUserGestureEnabled())
-      return true;
     if (hasUserGesture || isAllowedNavigation)
       return true;
+    // Frame-busting used to be generally allowed in most situations, but may
+    // now blocked if the document initiating the navigation has never received
+    // a user gesture.
+    if (!RuntimeEnabledFeatures::
+            framebustingNeedsSameOriginOrUserGestureEnabled()) {
+      String targetFrameDescription =
+          targetFrame.isLocalFrame()
+              ? "with URL '" +
+                    toLocalFrame(targetFrame).document()->url().getString() +
+                    "'"
+              : "with origin '" +
+                    targetFrame.securityContext()
+                        ->getSecurityOrigin()
+                        ->toString() +
+                    "'";
+      String message = "Frame with URL '" +
+                       toLocalFrame(this)->document()->url().getString() +
+                       "' attempted to navigate its top-level window " +
+                       targetFrameDescription +
+                       ". Navigating the top-level window from a cross-origin "
+                       "iframe will soon require that the iframe has received "
+                       "a user gesture. See "
+                       "https://www.chromestatus.com/features/"
+                       "5851021045661696.";
+      printNavigationWarning(message);
+      return true;
+    }
     errorReason =
         "The frame attempting navigation is targeting its top-level window, "
-        "but is neither same-origin with its target nor is it processing a "
+        "but is neither same-origin with its target nor has it received a "
         "user gesture. See "
         "https://www.chromestatus.com/features/5851021045661696.";
     printNavigationErrorMessage(targetFrame, errorReason.latin1().data());
     if (isLocalFrame())
       toLocalFrame(this)->navigationScheduler().schedulePageBlock(
           toLocalFrame(this)->document());
     return false;
   }
   if (!isAllowedNavigation && !errorReason.isNull())
     printNavigationErrorMessage(targetFrame, errorReason.latin1().data());
@@ skipping 128 matching lines @@
 
   ASSERT(page());
 
   if (m_owner)
     m_owner->setContentFrame(*this);
   else
     page()->setMainFrame(this);
 }
 
 }  // namespace blink