Inform the WebFrameClient of BeforeUnload/Unload handlers

Source/core/frame/LocalDOMWindow.cpp

Index: Source/core/frame/LocalDOMWindow.cpp
diff --git a/Source/core/frame/LocalDOMWindow.cpp b/Source/core/frame/LocalDOMWindow.cpp
index ee80a05b0ddfa044471e6f6a30942a0f01963611..f1b8ebc6bc82ac8507f303beabca82b9a0626671 100644
--- a/Source/core/frame/LocalDOMWindow.cpp
+++ b/Source/core/frame/LocalDOMWindow.cpp
@@ -231,6 +231,8 @@ static void addUnloadEventListener(LocalDOMWindow* domWindow)
     if (set.isEmpty())
         disableSuddenTermination();
     set.add(domWindow);
+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(
+        1, FrameLoaderClient::UnloadHandler);
 }
 
 static void removeUnloadEventListener(LocalDOMWindow* domWindow)
@@ -242,6 +244,8 @@ static void removeUnloadEventListener(LocalDOMWindow* domWindow)
     set.remove(it);
     if (set.isEmpty())
         enableSuddenTermination();

[Nate Chapin, 2015/01/20 18:46:49]

Will we eventually be able to remove these enable/disable calls?

[clamy, 2015/01/21 13:46:31]

Yes, when the chromium side patch lands we should remove those. However we
cannot get completely rid of blink::Platform::suddenTerminationChanged, because
we cannot track per-Frame the disables of sudden termination caused by pending
DOM local storage callbacks. It seems it has to be done per-process.

[Nate Chapin, 2015/01/21 19:51:42]

Interesting, I would have thought that local storage could be per-frame as well,
but I know nothing about the chromium-side implementation.

+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(

[Nate Chapin, 2015/01/20 18:46:49]

Is this safe? domWindow->frame() can be null at very annoying times.

[clamy, 2015/01/21 13:46:31]

In that case I added a check for domWindow->frame() before calling
suddenTerminationDisablerChanged. It did not seem to cause bot failures without
it though.

[Nate Chapin, 2015/01/21 19:51:42]

I did a quick look and didn't see anything that would prevent an attempt to add
an event listener to a detached window, but it may be difficult to get into that
situation in practice. I would not be at all surprised if we don't have test
coverage for it.

If you are willing to tolerate the risk of a fire drill, you could omit the
null-checks and be prepared to deal with a potential crash report in a couple
days. I'd lean toward including the null-checks just to be safe, though.

+        -1, FrameLoaderClient::UnloadHandler);
 }
 
 static void removeAllUnloadEventListeners(LocalDOMWindow* domWindow)
@@ -250,9 +254,12 @@ static void removeAllUnloadEventListeners(LocalDOMWindow* domWindow)
     DOMWindowSet::iterator it = set.find(domWindow);
     if (it == set.end())
         return;
+    int numHandlers = set.count(domWindow);
     set.removeAll(it);
     if (set.isEmpty())
         enableSuddenTermination();
+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(
+        -numHandlers, FrameLoaderClient::UnloadHandler);
 }
 
 static void addBeforeUnloadEventListener(LocalDOMWindow* domWindow)
@@ -261,6 +268,8 @@ static void addBeforeUnloadEventListener(LocalDOMWindow* domWindow)
     if (set.isEmpty())
         disableSuddenTermination();
     set.add(domWindow);
+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(
+        1, FrameLoaderClient::BeforeUnloadHandler);
 }
 
 static void removeBeforeUnloadEventListener(LocalDOMWindow* domWindow)
@@ -272,6 +281,8 @@ static void removeBeforeUnloadEventListener(LocalDOMWindow* domWindow)
     set.remove(it);
     if (set.isEmpty())
         enableSuddenTermination();
+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(
+        -1, FrameLoaderClient::BeforeUnloadHandler);
 }
 
 static void removeAllBeforeUnloadEventListeners(LocalDOMWindow* domWindow)
@@ -280,9 +291,12 @@ static void removeAllBeforeUnloadEventListeners(LocalDOMWindow* domWindow)
     DOMWindowSet::iterator it = set.find(domWindow);
     if (it == set.end())
         return;
+    int numHandlers = set.count(domWindow);
     set.removeAll(it);
     if (set.isEmpty())
         enableSuddenTermination();
+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(
+        -numHandlers, FrameLoaderClient::BeforeUnloadHandler);
 }
 
 static bool allowsBeforeUnloadListeners(LocalDOMWindow* window)