Compositor Animation Timelines: Fix frame swapping tests in WebFrameTest.cpp

third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp

Index: third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp b/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
index 94cae36c4d2075b1438d28417db77243c30bdaa9..dd3ac62a05b4365845aaedc6526e5dca111cb1f4 100644
--- a/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
+++ b/third_party/WebKit/Source/web/WebFrameWidgetImpl.cpp
@@ -604,6 +604,9 @@ bool WebFrameWidgetImpl::isAcceleratedCompositingActive() const
 
 void WebFrameWidgetImpl::willCloseLayerTreeView()
 {
+    if (page() && m_layerTreeView)

[dcheng, 2015/12/01 01:16:30]

Out of curiosity... how can we have a null page here? Can this get called on an
already detached frame?

[loyso (OOO), 2015/12/01 05:41:03]

There is a comment:
    // Returns the page object associated with this widget. This may be null
when
    // the page is shutting down, but will be valid at all other times.
    Page* page() const { return view()->page(); }
It's not completely clear, what the "shutting down" scope means.

But anyway, the lifetime scope for m_layerTreeView must be within the case when
frame is attached.

Fixed.

[loyso (OOO), 2015/12/01 06:45:39]

Well, we have it null here in fast/forms/ layout tests (see failed
webkit_tests).
It's called from RenderWidget::DoDeferredClose.

+        page()->willCloseLayerTreeView(*m_layerTreeView);
+
     setIsAcceleratedCompositingActive(false);
     m_layerTreeView = nullptr;
     m_layerTreeViewClosed = true;
@@ -978,6 +981,8 @@ void WebFrameWidgetImpl::initializeLayerTreeView()
         devTools->layerTreeViewChanged(m_layerTreeView);
 
     page()->settings().setAcceleratedCompositingEnabled(m_layerTreeView);
+    if (m_layerTreeView)
+        page()->layerTreeViewInitialized(*m_layerTreeView);
 
     // FIXME: only unittests, click to play, Android priting, and printing (for headers and footers)
     // make this assert necessary. We should make them not hit this code and then delete allowsBrokenNullLayerTreeView.