fix(Grid.js) Vertical scroll calculates height wrong with enableHoriz…

…ontalScrollbar: NEVER (angular-ui#6690)

* fix(Grid.js): ScrollIfNecessary does not account for scrollWidth correctly

Since scrollIfNecessary is called multiple times when enableCellEditOnFocus is true we need to make sure the scrollbarWidth and footerHeight is accounted for to not cause a loop.

fixes angular-ui#6653

* Add check for gridCol not null

Make sure gridCol is not null before checking for enableCellEditOnFocus

* fix(Grid.js) Vertical scroll calculates height wrong with enableHorizontalScrollbar: NEVER

Use scrollbarHeight instead of scrollbarWidth for vertical scroll calculations. scrollbarHeight has the value 0 when enableHorizontalScrollbar is set to NEVER.

Round calculated boundary values as computed style may have decimal number which will not match pixelsToSeeRow

src/js/core/factories/Grid.js

@@ -2402,7 +2402,7 @@ angular.module('ui.grid')
 
       // The bottom boundary is the current Y scroll position, plus the height of the grid, but minus the header height.
       //   Basically this is the viewport height added on to the scroll position
-      var bottomBound = self.renderContainers.body.prevScrollTop + self.gridHeight - self.renderContainers.body.headerHeight - self.footerHeight -  self.scrollbarWidth;
+      var bottomBound = self.renderContainers.body.prevScrollTop + self.gridHeight - self.renderContainers.body.headerHeight - self.footerHeight -  self.scrollbarHeight;
 
       // If there's a horizontal scrollbar, remove its height from the bottom boundary, otherwise we'll be letting it obscure rows
       //if (self.horizontalScrollbarHeight) {
@@ -2439,20 +2439,20 @@ angular.module('ui.grid')
         var scrollPixels;
 
         // If the scroll position we need to see the row is LESS than the top boundary, i.e. obscured above the top of the self...
-        if (pixelsToSeeRow < topBound) {
+        if (pixelsToSeeRow < Math.floor(topBound)) {
           // Get the different between the top boundary and the required scroll position and subtract it from the current scroll position\
           //   to get the full position we need
           scrollPixels = self.renderContainers.body.prevScrollTop - (topBound - pixelsToSeeRow);
 
           //Since scrollIfNecessary is called multiple times when enableCellEditOnFocus is true we need to make sure the scrollbarWidth and footerHeight is accounted for to not cause a loop.
           if (gridCol && gridCol.colDef && gridCol.colDef.enableCellEditOnFocus) {
-            scrollPixels = scrollPixels - self.footerHeight - self.scrollbarWidth;
+            scrollPixels = scrollPixels - self.footerHeight - self.scrollbarHeight;
           }
 
           scrollEvent.y = getScrollY(scrollPixels, scrollLength, self.renderContainers.body.prevScrolltopPercentage);
         }
         // Otherwise if the scroll position we need to see the row is MORE than the bottom boundary, i.e. obscured below the bottom of the self...
-        else if (pixelsToSeeRow > bottomBound) {
+        else if (pixelsToSeeRow > Math.ceil(bottomBound)) {
           // Get the different between the bottom boundary and the required scroll position and add it to the current scroll position
           //   to get the full position we need
           scrollPixels = pixelsToSeeRow - bottomBound + self.renderContainers.body.prevScrollTop;