Files.app: Cancel all selections on ESC key.

BUG=459462
TEST=check that ESC cancels selections on list/grid view, and that pressing ESC while renaming doesn't cancel selection.

Review URL: https://codereview.chromium.org/970103002

Cr-Commit-Position: refs/heads/master@{#318856}

ui/file_manager/file_manager/foreground/js/ui/file_table.js

@@ -1127,6 +1127,13 @@ filelist.handleKeyDown = function(e) {
     return;
   }
 
+  // Esc
+  if (e.keyCode === 27 && !e.ctrlKey && !e.shiftKey) {
+    sm.unselectAll();
+    e.preventDefault();
+    return;
+  }
+
   // Space
   if (e.keyCode == SPACE_KEY_CODE) {
     if (leadIndex != -1) {