lok - sc: row/column headers are updated faster

Now the computation of the row/column headers data exploits the cached
row/col positions in HeightHelper/WidthHelper.

That makes updating row/column headers at the bottom of the document
as fast as at the top even for very big spreadsheets.

Change-Id: I27381b520aaed68662e4d07c5879046d182c70e6
Reviewed-on: https://gerrit.libreoffice.org/40451Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Marco Cecchetti <mrcekets@gmail.com>

desktop/qa/desktop_lib/test_desktop_lib.cxx

@@ -639,7 +639,7 @@ void DesktopLOKTest::testRowColumnHeaders()
         if (bFirstHeader)
         {
             CPPUNIT_ASSERT(nSize <= nY);
-            CPPUNIT_ASSERT_EQUAL(OString("11"), aText);
+            CPPUNIT_ASSERT_EQUAL(OString("10"), aText);
             bFirstHeader = false;
         }
         else
@@ -666,7 +666,7 @@ void DesktopLOKTest::testRowColumnHeaders()
         if (bFirstHeader)
         {
             CPPUNIT_ASSERT(nSize <= nX);
-            CPPUNIT_ASSERT_EQUAL(OString("4"), aText);
+            CPPUNIT_ASSERT_EQUAL(OString("3"), aText);
             bFirstHeader = false;
         }
         else

include/sal/log-areas.dox

@@ -132,6 +132,7 @@ certain functionality.
 @li @c sc.core.grouparealistener - sc::FormulaGroupAreaListener
 @li @c sc.filter - Calc filter
 @li @c sc.lok.docsize
+@li @c sc.lok.header
 @li @c sc.lok.poshelper
 @li @c sc.opencl - OpenCL-related stuff in general
 @li @c sc.opencl.source - Generated OpenCL source code

sc/source/ui/inc/tabview.hxx

@@ -196,6 +196,11 @@ private:
 
     double              mfPendingTabBarWidth;       // Tab bar width relative to frame window width.
 
+    SCROW               mnLOKStartHeaderRow;
+    SCROW               mnLOKEndHeaderRow;
+    SCCOL               mnLOKStartHeaderCol;
+    SCCOL               mnLOKEndHeaderCol;
+
     bool                bMinimized:1;
     bool                bInUpdateHeader:1;
     bool                bInActivatePart:1;