Don't recalculate columns if only height has changed (#18274)

This patch increases the reported fps in GridResizeTerror from 12 to 35
in my Chrome if only changing the height. No automatic test since
performance testing on our shared testing infrastructure would be quite
error-prone.

Change-Id: I17aeb2eac9fe4ef72993eb0f9307c1d5a75653a2

1 files changed, 5 insertions, 1 deletions

diff --git a/client/src/com/vaadin/client/widgets/Grid.java b/client/src/com/vaadin/client/widgets/Grid.java
index b3edca9140..fef6a01640 100644
--- a/client/src/com/vaadin/client/widgets/Grid.java
+++ b/client/src/com/vaadin/client/widgets/Grid.java
@@ -2585,6 +2585,7 @@ public class Grid<T> extends ResizeComposite implements
 
     /** @see Grid#autoColumnWidthsRecalculator */
     private class AutoColumnWidthsRecalculator {
+        private double lastCalculatedInnerWidth = -1;
 
         private final ScheduledCommand calculateCommand = new ScheduledCommand() {
 
@@ -2619,6 +2620,7 @@ public class Grid<T> extends ResizeComposite implements
                 } else {
                     calculate();
                 }
+                lastCalculatedInnerWidth = escalator.getInnerWidth();
             }
         };
 
@@ -7656,7 +7658,9 @@ public class Grid<T> extends ResizeComposite implements
 
             @Override
             public void execute() {
-                recalculateColumnWidths();
+                if (escalator.getInnerWidth() != autoColumnWidthsRecalculator.lastCalculatedInnerWidth) {
+                    recalculateColumnWidths();
+                }
             }
         });
     }