Replace wxSizer::RecalcSizes() with RepositionChildren()

The new method takes minimal size just computed by RecalcSizes() as its
argument making it unnecessary to store it as a member variable in the derived
classes such as wx{Box,FlexGrid}Sizer.

The old method can still be overridden for compatibility and by the derived
class that don't need minimal size when updating children.

include/wx/wrapsizer.h

@@ -36,7 +36,7 @@ public:
 
     // override base class virtual methods
     virtual wxSize CalcMin() wxOVERRIDE;
-    virtual void RecalcSizes() wxOVERRIDE;
+    virtual void RepositionChildren(const wxSize& minSize) wxOVERRIDE;
 
     virtual bool InformFirstDirection(int direction,
                                       int size,
@@ -84,13 +84,17 @@ protected:
     bool m_lastUsed;         // Indicates whether value from InformFirst... has
                              //  been used yet
 
-    // The sizes below are computed by RecalcSizes(), i.e. they don't have
+    // The sizes below are computed by RepositionChildren(), i.e. they don't have
     // valid values during the initial call to CalcMin() and they are only
     // valid for the current layout (i.e. the current number of rows)
     int m_minSizeMinor;      // Min size in minor direction
     int m_maxSizeMajor;      // Size of longest row
     int m_minItemMajor;      // Size of smallest item in major direction
 
+    // the minimal size needed for this sizer as calculated by the last call to
+    // our CalcMin()
+    wxSize m_calculatedMinSize;
+
     wxBoxSizer m_rows;       // Sizer containing multiple rows of our items
 
     wxDECLARE_DYNAMIC_CLASS_NO_COPY(wxWrapSizer);