PlzNavigate: stop navigations when opening a document for write

content/common/frame_messages.h

Index: content/common/frame_messages.h
diff --git a/content/common/frame_messages.h b/content/common/frame_messages.h
index 4285e17a394c8c50a548ba32f5f79e6bb90bfb5f..debc0173dbb278e34e4bf15c99f4ee8d31da96a7 100644
--- a/content/common/frame_messages.h
+++ b/content/common/frame_messages.h
@@ -360,6 +360,7 @@ IPC_STRUCT_TRAITS_BEGIN(content::BeginNavigationParams)
   IPC_STRUCT_TRAITS_MEMBER(searchable_form_encoding)
   IPC_STRUCT_TRAITS_MEMBER(initiator_origin)
   IPC_STRUCT_TRAITS_MEMBER(client_side_redirect_url)
+  IPC_STRUCT_TRAITS_MEMBER(renderer_navigation_id)
 IPC_STRUCT_TRAITS_END()
 
 IPC_STRUCT_TRAITS_BEGIN(content::StartNavigationParams)
@@ -883,6 +884,12 @@ IPC_MESSAGE_ROUTED4(FrameMsg_CommitNavigation,
                     content::RequestNavigationParams  /* request_params */)
 
 // PlzNavigate
+// Informs the renderer that the browser stopped processing a renderer-initiated
+// navigation.
+IPC_MESSAGE_ROUTED1(FrameMsg_DroppedNavigation,
+                    int /* renderer_navigation_id */)
+
+// PlzNavigate
 // Tells the renderer that a navigation failed with the error code |error_code|
 // and that the renderer should display an appropriate error page.
 IPC_MESSAGE_ROUTED4(FrameMsg_FailedNavigation,
@@ -1477,6 +1484,11 @@ IPC_MESSAGE_ROUTED2(FrameHostMsg_BeginNavigation,
                     content::CommonNavigationParams,
                     content::BeginNavigationParams)
 
+// PlzNavigate
+// Tells the browser to abort an ongoing renderer-initiated navigation. This is
+// used when the page calls document.open.
+IPC_MESSAGE_ROUTED0(FrameHostMsg_AbortNavigation)
+
 // Sent as a response to FrameMsg_VisualStateRequest.
 // The message is delivered using RenderWidget::QueueMessage.
 IPC_MESSAGE_ROUTED1(FrameHostMsg_VisualStateResponse, uint64_t /* id */)