Fixes a few Escalator regressions relating to IE8 and IE9 (#13334)

Change-Id: I3446d1f781f5aa5e3262a20f51999b0a52d48dd3

WebContent/VAADIN/themes/base/escalator/escalator.scss

@@ -67,15 +67,18 @@ $border-color: #aaa;
 .#{$primaryStyleName}-row {
 	display: block;
 	
-	.v-ie8 & {
-		/* IE8 doesn't let table rows be longer than body only with display block. Moar hax. */
+	.v-ie8 &, .v-ie9 & {
+		/* 
+		 * Neither IE8 nor IE9 let table rows be longer than tbody, with only 
+		 * "display: block". Moar hax. 
+		 */
 		float: left;
 		clear: left;
 		
 		/* 
-		 * The inline style of margin-top from the <tbody> to offset the header's dimension is, 
-		 * for some strange reason, inherited into each contained <tr>. 
-		 * We need to cancel it: 
+		 * The inline style of margin-top from the <tbody> to offset the 
+		 * header's dimension is, for some strange reason, inherited into each
+		 * contained <tr>. We need to cancel it:
 		 */
 		margin-top: 0;
 	}

client/src/com/vaadin/client/ui/grid/ScrollbarBundle.java

@@ -312,7 +312,7 @@ abstract class ScrollbarBundle {
      *            the length of the scrollbar in pixels
      */
     public final void setOffsetSize(double px) {
-        internalSetOffsetSize(truncate(px));
+        internalSetOffsetSize(Math.max(0, truncate(px)));
         forceScrollbar(showsScrollHandle());
         recalculateMaxScrollPos();
         fireVisibilityChangeIfNeeded();
@@ -360,7 +360,7 @@ abstract class ScrollbarBundle {
              * large numbers (as of today, 25.3.2014). This double-ranged is
              * only facilitating future virtual scrollbars.
              */
-            internalSetScrollPos(toInt32(px));
+            internalSetScrollPos(toInt32(scrollPos));
         }
     }
 
@@ -445,7 +445,7 @@ abstract class ScrollbarBundle {
      *            through
      */
     public final void setScrollSize(double px) {
-        internalSetScrollSize(toInt32(truncate(px)));
+        internalSetScrollSize(toInt32(Math.max(0, truncate(px))));
         forceScrollbar(showsScrollHandle());
         recalculateMaxScrollPos();
         fireVisibilityChangeIfNeeded();
@@ -485,7 +485,7 @@ abstract class ScrollbarBundle {
      */
     public final void setScrollbarThickness(int px) {
         isInvisibleScrollbar = (px == 0);
-        internalSetScrollbarThickness(px != 0 ? px
+        internalSetScrollbarThickness(px != 0 ? Math.max(0, px)
                 : OSX_INVISIBLE_SCROLLBAR_FAKE_SIZE_PX);
     }
 
@@ -572,7 +572,6 @@ abstract class ScrollbarBundle {
         }
     }
 
-
     /**
      * Converts a double into an integer by JavaScript's terms.
      * <p>