Push UNITS_PROVIDER down into a low-level mixin.

This allows us to also construct cheap UNIT_PROVIDERs for specific
tasks when necessary.

common/eda_base_frame.cpp

@@ -124,7 +124,6 @@ void EDA_BASE_FRAME::commonInit( FRAME_T aFrameType )
     m_supportsAutoSave  = false;
     m_autoSaveState     = false;
     m_undoRedoCountMax  = DEFAULT_MAX_UNDO_ITEMS;
-    m_userUnits         = EDA_UNITS::MILLIMETRES;
     m_isClosing         = false;
     m_isNonUserClose    = false;
     m_autoSaveTimer     = new wxTimer( this, ID_AUTO_SAVE_TIMER );
@@ -153,21 +152,14 @@ void EDA_BASE_FRAME::commonInit( FRAME_T aFrameType )
 }
 
 
-EDA_BASE_FRAME::EDA_BASE_FRAME( FRAME_T aFrameType, KIWAY* aKiway ) :
-        wxFrame(),
-        TOOLS_HOLDER(),
-        KIWAY_HOLDER( aKiway, KIWAY_HOLDER::FRAME )
-{
-    commonInit( aFrameType );
-}
-
-
-EDA_BASE_FRAME::EDA_BASE_FRAME( wxWindow* aParent, FRAME_T aFrameType,
-                                const wxString& aTitle, const wxPoint& aPos, const wxSize& aSize,
-                                long aStyle, const wxString& aFrameName, KIWAY* aKiway ) :
+EDA_BASE_FRAME::EDA_BASE_FRAME( wxWindow* aParent, FRAME_T aFrameType, const wxString& aTitle,
+                                const wxPoint& aPos, const wxSize& aSize, long aStyle,
+                                const wxString& aFrameName, KIWAY* aKiway,
+                                const EDA_IU_SCALE& aIuScale ) :
         wxFrame( aParent, wxID_ANY, aTitle, aPos, aSize, aStyle, aFrameName ),
         TOOLS_HOLDER(),
-        KIWAY_HOLDER( aKiway, KIWAY_HOLDER::FRAME )
+        KIWAY_HOLDER( aKiway, KIWAY_HOLDER::FRAME ),
+        UNITS_PROVIDER( aIuScale, EDA_UNITS::MILLIMETRES )
 {
     commonInit( aFrameType );
 }