Constify vcl::Window child lookup

Also removes the function comments before the implementations,
as these are just the same as already in the header.

Change-Id: I11425dc4aa372423fcf469ab1374159ce8b180e2
Reviewed-on: https://gerrit.libreoffice.org/61035
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

include/vcl/layout.hxx

@@ -767,21 +767,21 @@ public:
 //i.e. acts like pChild = pChild->GetWindow(GetWindowType::FirstChild);
 //in a flat hierarchy where dialogs only have one layer
 //of children
-VCL_DLLPUBLIC vcl::Window* firstLogicalChildOfParent(vcl::Window *pTopLevel);
+VCL_DLLPUBLIC vcl::Window* firstLogicalChildOfParent(const vcl::Window *pTopLevel);
 
 //Get next window after pChild of a pTopLevel window as
 //if any intermediate layout widgets didn't exist
 //i.e. acts like pChild = pChild->GetWindow(GetWindowType::Next);
 //in a flat hierarchy where dialogs only have one layer
 //of children
-VCL_DLLPUBLIC vcl::Window* nextLogicalChildOfParent(vcl::Window *pTopLevel, vcl::Window *pChild);
+VCL_DLLPUBLIC vcl::Window* nextLogicalChildOfParent(const vcl::Window *pTopLevel, const vcl::Window *pChild);
 
 //Get previous window before pChild of a pTopLevel window as
 //if any intermediate layout widgets didn't exist
 //i.e. acts like pChild = pChild->GetWindow(GetWindowType::Prev);
 //in a flat hierarchy where dialogs only have one layer
 //of children
-VCL_DLLPUBLIC vcl::Window* prevLogicalChildOfParent(vcl::Window *pTopLevel, vcl::Window *pChild);
+VCL_DLLPUBLIC vcl::Window* prevLogicalChildOfParent(const vcl::Window *pTopLevel, const vcl::Window *pChild);
 
 //Returns true is the Window has a single child which is a container
 VCL_DLLPUBLIC bool isLayoutEnabled(const vcl::Window *pWindow);

vcl/source/window/dialog.cxx

@@ -126,11 +126,9 @@ void ImplHideSplash()
             pSVData->mpIntroWindow->Hide();
 }
 
-//Get next window after pChild of a pTopLevel window as
-//if any intermediate layout widgets didn't exist
-vcl::Window * nextLogicalChildOfParent(vcl::Window *pTopLevel, vcl::Window *pChild)
+vcl::Window * nextLogicalChildOfParent(const vcl::Window *pTopLevel, const vcl::Window *pChild)
 {
-    vcl::Window *pLastChild = pChild;
+    const vcl::Window *pLastChild = pChild;
 
     if (isContainerWindow(*pChild))
         pChild = pChild->GetWindow(GetWindowType::FirstChild);
@@ -151,12 +149,12 @@ vcl::Window * nextLogicalChildOfParent(vcl::Window *pTopLevel, vcl::Window *pChi
     if (pChild && isContainerWindow(*pChild))
         pChild = nextLogicalChildOfParent(pTopLevel, pChild);
 
-    return pChild;
+    return const_cast<vcl::Window *>(pChild);
 }
 
-vcl::Window * prevLogicalChildOfParent(vcl::Window *pTopLevel, vcl::Window *pChild)
+vcl::Window * prevLogicalChildOfParent(const vcl::Window *pTopLevel, const vcl::Window *pChild)
 {
-    vcl::Window *pLastChild = pChild;
+    const vcl::Window *pLastChild = pChild;
 
     if (isContainerWindow(*pChild))
         pChild = pChild->GetWindow(GetWindowType::LastChild);
@@ -177,17 +175,15 @@ vcl::Window * prevLogicalChildOfParent(vcl::Window *pTopLevel, vcl::Window *pChi
     if (pChild && isContainerWindow(*pChild))
         pChild = prevLogicalChildOfParent(pTopLevel, pChild);
 
-    return pChild;
+    return const_cast<vcl::Window *>(pChild);
 }
 
-//Get first window of a pTopLevel window as
-//if any intermediate layout widgets didn't exist
-vcl::Window * firstLogicalChildOfParent(vcl::Window *pTopLevel)
+vcl::Window * firstLogicalChildOfParent(const vcl::Window *pTopLevel)
 {
-    vcl::Window *pChild = pTopLevel->GetWindow(GetWindowType::FirstChild);
+    const vcl::Window *pChild = pTopLevel->GetWindow(GetWindowType::FirstChild);
     if (pChild && isContainerWindow(*pChild))
         pChild = nextLogicalChildOfParent(pTopLevel, pChild);
-    return pChild;
+    return const_cast<vcl::Window *>(pChild);
 }
 
 void Accelerator::GenerateAutoMnemonicsOnHierarchy(vcl::Window* pWindow)