Files.app: Use <button> instead of <paper-button> to make ENTER and SPACE effective on them.

ui/file_manager/integration_tests/file_manager/file_dialog.js

Index: ui/file_manager/integration_tests/file_manager/file_dialog.js
diff --git a/ui/file_manager/integration_tests/file_manager/file_dialog.js b/ui/file_manager/integration_tests/file_manager/file_dialog.js
index 8645a93eb714c8bdd6cbb10dc1d7434103fc9e3b..92f4c010e68362a0128e8a19bd8c4e782f12b62c 100644
--- a/ui/file_manager/integration_tests/file_manager/file_dialog.js
+++ b/ui/file_manager/integration_tests/file_manager/file_dialog.js
@@ -76,12 +76,12 @@ function openFileDialog(volumeName, expectedSet) {
         expectedSet,
         function(windowId) {
           return remoteCall.waitForElement(windowId,
-                                           '.button-panel paper-button.cancel').
+                                           '.button-panel button.cancel').
               then(function() {
                 return remoteCall.callRemoteTestUtil(
                     'fakeEvent',
                     windowId,
-                    ['.button-panel paper-button.cancel', 'click']);
+                    ['.button-panel button.cancel', 'click']);
               });
         });
   }).then(function(result) {
@@ -110,12 +110,12 @@ function openFileDialog(volumeName, expectedSet) {
         expectedSet,
         function(windowId) {
           return remoteCall.waitForElement(windowId,
-                                           '.button-panel paper-button.ok').
+                                           '.button-panel button.ok').
               then(function() {
                 return remoteCall.callRemoteTestUtil(
                     'fakeEvent',
                     windowId,
-                    ['.button-panel paper-button.ok', 'click']);
+                    ['.button-panel button.ok', 'click']);
               });
         });
   }).then(function(result) {