Added "kernels" pass stage to compiler, removed unused opaque from cv::gimpl::Op

modules/gapi/src/compiler/gcompiler.cpp

@@ -104,11 +104,13 @@ cv::gimpl::GCompiler::GCompiler(const cv::GComputation &c,
 
     // Remove GCompoundBackend to avoid calling setupBackend() with it in the list
     m_all_kernels.remove(cv::gapi::compound::backend());
-    m_e.addPass("init", "resolve_kernels", std::bind(passes::resolveKernels, _1,
+
+    m_e.addPassStage("kernels");
+    m_e.addPass("kernels", "resolve_kernels", std::bind(passes::resolveKernels, _1,
                                                      std::ref(m_all_kernels), // NB: and not copied here
                                                      lookup_order));
+    m_e.addPass("kernels", "check_islands_content", passes::checkIslandsContent);
 
-    m_e.addPass("init", "check_islands_content", passes::checkIslandsContent);
     m_e.addPassStage("meta");
     m_e.addPass("meta", "initialize",   std::bind(passes::initMeta, _1, std::ref(m_metas)));
     m_e.addPass("meta", "propagate",    std::bind(passes::inferMeta, _1, false));

modules/gapi/src/compiler/gmodel.cpp

@@ -26,7 +26,7 @@ ade::NodeHandle GModel::mkOpNode(GModel::Graph &g, const GKernel &k, const std::
     ade::NodeHandle op_h = g.createNode();
     g.metadata(op_h).set(NodeType{NodeType::OP});
     //These extra empty {} are to please GCC (-Wmissing-field-initializers)
-    g.metadata(op_h).set(Op{k, args, {}, {}, {}});
+    g.metadata(op_h).set(Op{k, args, {}, {}});
     if (!island.empty())
         g.metadata(op_h).set(Island{island});
     return op_h;

modules/gapi/src/compiler/gmodel.hpp

@@ -61,7 +61,6 @@ struct Op
     std::vector<RcDesc> outs; // TODO: Introduce a new type for resource references
 
     cv::gapi::GBackend  backend;
-    util::any           opaque;
 };
 
 struct Data