Make escape in the search box abort the search

Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/src/main/java/com/google/gerrit/client/SearchPanel.java b/src/main/java/com/google/gerrit/client/SearchPanel.java
index 6a9aa8e..9d2de13 100644
--- a/src/main/java/com/google/gerrit/client/SearchPanel.java
+++ b/src/main/java/com/google/gerrit/client/SearchPanel.java
@@ -67,8 +67,14 @@
     searchBox.addKeyPressHandler(new KeyPressHandler() {
       @Override
       public void onKeyPress(final KeyPressEvent event) {
-        if (event.getCharCode() == KeyCodes.KEY_ENTER) {
-          doSearch();
+        switch (event.getCharCode()) {
+          case KeyCodes.KEY_ENTER:
+            doSearch();
+            break;
+          case KeyCodes.KEY_ESCAPE:
+            searchBox.setText("");
+            searchBox.setFocus(false);
+            break;
         }
       }
     });