[oneD] change thermo type passed to StFlow constructor

- allow for 'ThermoPhase`, and cast to 'IdealGasPhase' internally

include/cantera/oneD/StFlow.h

@@ -45,7 +45,12 @@ public:
     //!     to evaluate all thermodynamic, kinetic, and transport properties.
     //! @param nsp Number of species.
     //! @param points Initial number of grid points
-    StFlow(IdealGasPhase* ph = 0, size_t nsp = 1, size_t points = 1);
+    StFlow(ThermoPhase* ph = 0, size_t nsp = 1, size_t points = 1);
+
+    //! Delegating constructor
+    StFlow(shared_ptr<ThermoPhase> th, size_t nsp = 1, size_t points = 1) :
+        StFlow(th.get(), nsp, points) {
+    }
 
     //! @name Problem Specification
     //! @{

samples/cxx/flamespeed/flamespeed.cpp

@@ -17,7 +17,7 @@ int flamespeed(double phi)
 {
     try {
         auto sol = newSolution("gri30.yaml", "gri30", "None");
-        auto gas = std::dynamic_pointer_cast<IdealGasPhase>(sol->thermo());
+        auto gas = sol->thermo();
         double temp = 300.0; // K
         double pressure = 1.0*OneAtm; //atm
         double uin = 0.3; //m/sec
@@ -51,7 +51,7 @@ int flamespeed(double phi)
 
         //-------- step 1: create the flow -------------
 
-        StFlow flow(gas.get());
+        StFlow flow(gas);
         flow.setFreeFlow();
 
         // create an initial grid

src/oneD/StFlow.cpp

@@ -13,7 +13,7 @@ using namespace std;
 namespace Cantera
 {
 
-StFlow::StFlow(IdealGasPhase* ph, size_t nsp, size_t points) :
+StFlow::StFlow(ThermoPhase* ph, size_t nsp, size_t points) :
     Domain1D(nsp+c_offset_Y, points),
     m_press(-1.0),
     m_nsp(nsp),
@@ -30,9 +30,14 @@ StFlow::StFlow(IdealGasPhase* ph, size_t nsp, size_t points) :
     m_zfixed(Undef),
     m_tfixed(Undef)
 {
+    if (ph->type() == "IdealGas") {
+        m_thermo = (IdealGasPhase*)ph;
+    } else {
+        throw CanteraError("StFlow::StFlow",
+                           "Unsupported phase type: need 'IdealGasPhase'");
+    }
     m_type = cFlowType;
     m_points = points;
-    m_thermo = ph;
 
     if (ph == 0) {
         return; // used to create a dummy object