Remove the hack with changing the parent background colour in wxInfoBar.

Finding the closest info bar to copy the background colour from only worked
for very simple layouts and failed for more complicated ones with nested
sizers so don't try to change the colour automatically, it's easy enough to do
it manually as shown in the updated dialogs sample.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62301 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/infobar.h

@@ -97,12 +97,6 @@ private:
     // handler for the close button
     void OnButton(wxCommandEvent& event);
 
-    // change the parent background colour to match that of our sibling
-    void ChangeParentBackground();
-
-    // restore the parent background changed by the above function
-    void RestoreParentBackground();
-
     // show/hide the bar
     void DoShow();
     void DoHide();
@@ -118,9 +112,6 @@ private:
                  m_hideEffect;
     int m_effectDuration;
 
-    // the original parent background colour, before we changed it
-    wxColour m_origParentBgCol;
-
     DECLARE_EVENT_TABLE()
     wxDECLARE_NO_COPY_CLASS(wxInfoBarGeneric);
 };