Clear a stray ref on layers when purging GL resourcesv5.4.0-rc1

Fix a regression of 3df57f7e550a19cb4450ed3896aa51ddb38c2ed2 where
a reference to TextureMapperBackingStore would be kept in the
TextureMapperLayers after purgeGLResources(). This would crash later
on if the window would get destroyed before the
CoordinatedGraphicsScene that own those layers.

Task-number: QTBUG-40734
Change-Id: Id1a596c0f0ba9afd1e163f83c38dda939f521314
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@theqtcompany.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/Source/WebCore/platform/graphics/texmap/coordinated/CoordinatedGraphicsScene.cpp b/Source/WebCore/platform/graphics/texmap/coordinated/CoordinatedGraphicsScene.cpp
index acd382cdb..b9709136d 100644
--- a/Source/WebCore/platform/graphics/texmap/coordinated/CoordinatedGraphicsScene.cpp
+++ b/Source/WebCore/platform/graphics/texmap/coordinated/CoordinatedGraphicsScene.cpp
@@ -694,6 +694,10 @@ void CoordinatedGraphicsScene::purgeGLResources()
     m_backingStores.clear();
     m_backingStoresWithPendingBuffers.clear();
 
+    LayerMap::iterator end = m_layers.end();
+    for (LayerMap::iterator it = m_layers.begin(); it != end; ++it)
+        it->value->setBackingStore(0);
+
     setActive(false);
     dispatchOnMainThread(bind(&CoordinatedGraphicsScene::purgeBackingStores, this));
 }