Fix backwards compatibility

QtWebEngine supports building with last stable and last LTS Qt releases.

Guard some 5.7-5.9 API from being used when not available, and reinstate
the default features for 5.6 LTS builds.

Change-Id: Ia288a49109d011a2bee883d4a2d38d994b497d59
Reviewed-by: Michael Brüning <michael.bruning@qt.io>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/core/delegated_frame_node.cpp b/src/core/delegated_frame_node.cpp
index a4b2a4036..e49bc553f 100644
--- a/src/core/delegated_frame_node.cpp
+++ b/src/core/delegated_frame_node.cpp
@@ -209,6 +209,7 @@ protected:
     QVector<QSGNode*> *m_sceneGraphNodes;
 };
 
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 8, 0))
 class DelegatedNodeTreeUpdater : public DelegatedNodeTreeHandler
 {
 public:
@@ -303,6 +304,7 @@ public:
 private:
     QVector<QSGNode*>::iterator m_nodeIterator;
 };
+#endif
 
 class DelegatedNodeTreeCreator : public DelegatedNodeTreeHandler
 {
@@ -872,8 +874,13 @@ void DelegatedFrameNode::commit(ChromiumCompositorData *chromiumCompositorData,
     // We first compare if the render passes from the previous frame data are structurally
     // equivalent to the render passes in the current frame data. If they are, we are going
     // to reuse the old nodes. Otherwise, we will delete the old nodes and build a new tree.
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 8, 0))
     cc::DelegatedFrameData *previousFrameData = m_chromiumCompositorData->previousFrameData.get();
     const bool buildNewTree = !areRenderPassStructuresEqual(frameData, previousFrameData) || m_sceneGraphNodes.empty();
+#else
+    // No updates possible with old scenegraph nodes
+    const bool buildNewTree = true;
+#endif
 
     m_chromiumCompositorData->previousFrameData = nullptr;
     SGObjects previousSGObjects;
@@ -887,11 +894,13 @@ void DelegatedFrameNode::commit(ChromiumCompositorData *chromiumCompositorData,
             delete oldChain;
         m_sceneGraphNodes.clear();
         nodeHandler.reset(new DelegatedNodeTreeCreator(&m_sceneGraphNodes, apiDelegate));
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 8, 0))
     } else {
         // Save the texture strong refs so they only go out of scope when the method returns and
         // the new vector of texture strong refs has been filled.
         qSwap(m_sgObjects.textureStrongRefs, textureStrongRefs);
         nodeHandler.reset(new DelegatedNodeTreeUpdater(&m_sceneGraphNodes));
+#endif
     }
     // The RenderPasses list is actually a tree where a parent RenderPass is connected
     // to its dependencies through a RenderPassId reference in one or more RenderPassQuads.