Keep track in the browser of which frames have onunload and onbeforeunload handlers.

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index acb7916dafaa6adc64f982046ca89ddb0ebc838d..61cd6ca6a8bb3ef3fe4f1ea6e608e7130e4bad9c 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -378,6 +378,8 @@ RenderFrameHostImpl::RenderFrameHostImpl(SiteInstance* site_instance,
       is_waiting_for_swapout_ack_(false),
       render_frame_created_(false),
       navigations_suspended_(false),
+      has_beforeunload_handlers_(false),
+      has_unload_handlers_(false),
       is_waiting_for_beforeunload_ack_(false),
       unload_ack_is_for_navigation_(false),
       is_loading_(false),
@@ -751,6 +753,10 @@ bool RenderFrameHostImpl::OnMessageReceived(const IPC::Message &msg) {
     IPC_MESSAGE_HANDLER(FrameHostMsg_DocumentOnLoadCompleted,
                         OnDocumentOnLoadCompleted)
     IPC_MESSAGE_HANDLER(FrameHostMsg_BeforeUnload_ACK, OnBeforeUnloadACK)
+    IPC_MESSAGE_HANDLER(FrameHostMsg_BeforeUnloadHandlersPresent,
+                        OnBeforeUnloadHandlersPresent)
+    IPC_MESSAGE_HANDLER(FrameHostMsg_UnloadHandlersPresent,
+                        OnUnloadHandlersPresent)
     IPC_MESSAGE_HANDLER(FrameHostMsg_SwapOut_ACK, OnSwapOutACK)
     IPC_MESSAGE_HANDLER(FrameHostMsg_ContextMenu, OnContextMenu)
     IPC_MESSAGE_HANDLER(FrameHostMsg_JavaScriptExecuteResponse,
@@ -2373,6 +2379,14 @@ void RenderFrameHostImpl::OnSetHasReceivedUserGesture() {
   frame_tree_node_->OnSetHasReceivedUserGesture();
 }
 
+void RenderFrameHostImpl::OnBeforeUnloadHandlersPresent(bool present) {
+  has_beforeunload_handlers_ = present;
+}
+
+void RenderFrameHostImpl::OnUnloadHandlersPresent(bool present) {
+  has_unload_handlers_ = present;
+}
+
 #if BUILDFLAG(USE_EXTERNAL_POPUP_MENU)
 void RenderFrameHostImpl::OnShowPopup(
     const FrameHostMsg_ShowPopup_Params& params) {
@@ -2701,7 +2715,25 @@ void RenderFrameHostImpl::SimulateBeforeUnloadAck() {
 }
 
 bool RenderFrameHostImpl::ShouldDispatchBeforeUnload() {
-  return IsRenderFrameLive();
+  if (!IsRenderFrameLive())
+    return false;
+
+  for (FrameTreeNode* node : frame_tree_->SubtreeNodes(frame_tree_node_)) {
+    if (node->current_frame_host()->has_beforeunload_handlers_)
+      return true;
+  }
+  return false;
+}
+
+bool RenderFrameHostImpl::ShouldDispatchUnload() {

[nasko, 2017/03/29 21:45:17]

This actually doesn't make sense to have. On cross-process navigations, the act
of swapping out the old RenderFrameHost will run the unload handler, if one is
present. In same-process navigations, it will be done entirely internally to
Blink, so content/ doesn't have to care at all. Certainly the browser side
doesn't need to know about this.

+  if (!IsRenderFrameLive())
+    return false;
+
+  for (FrameTreeNode* node : frame_tree_->SubtreeNodes(frame_tree_node_)) {
+    if (node->current_frame_host()->has_unload_handlers_)
+      return true;
+  }
+  return false;
 }
 
 void RenderFrameHostImpl::UpdateOpener() {