Layout transitions triggered on key-down instead of key-up.

ui/keyboard/resources/elements/kb-keyboard.html

 <!--
   -- Copyright 2013 The Chromium Authors. All rights reserved.
   -- Use of this source code is governed by a BSD-style license that can be
   -- found in the LICENSE file.
   -->
 
 <polymer-element name="kb-keyboard" on-key-over="keyOver" on-key-up="keyUp"
     on-key-down="keyDown" on-key-longpress="keyLongpress" on-pointerup="up"
     on-pointerdown="down" on-enable-sel="enableSel"
     on-enable-dbl="enableDbl" attributes="keyset layout rows capsLocked">
@@ skipping 271 matching lines @@
        */
       keyDown: function(event, detail) {
         if (this.skipEvent(detail))
           return;
 
         if (this.lastPressedKey)
           this.lastPressedKey.classList.remove('active');
         this.lastPressedKey = event.target;
         this.lastPressedKey.classList.add('active');
         repeatKey.cancel();
+
+        var char = detail.char;
+        switch(char) {
+          case 'Shift':
+            // Removes caps-lock if caps-locked.
+            if(this.classList.contains('caps-locked')) {
+              this.classList.remove('caps-locked');
+            }
+            break;
+          default:
+            break;
+        }
+
+        // A transition key was pressed, immediately move to new keyset.
         var toKeyset = detail.toKeyset;
         if (toKeyset) {
           this.keyset = toKeyset;
           this.querySelector('#' + this.layout + '-' + this.keyset).nextKeyset =
               detail.nextKeyset;
           return;
         }
 
         if (detail.repeat) {
           this.keyTyped(detail);
@@ skipping 90 matching lines @@
           return;
         if (swipeInProgress)
           return;
         this.lastPressedKey.classList.remove('active');
         if (this.lastPressedKey != event.target)
           return;
         if (repeatKey.key == event.target) {
           repeatKey.cancel();
           return;
         }
         var toKeysetId = detail.toKeyset;

[bshe, 2013/09/16 17:52:01]

It is probably worth mention in a comment here about why we still have keyset
transition code here. I believe for non caps uppers case, this is still
necessary?

[rsadam, 2013/09/16 18:23:49]

Done.

         // Keyset transition key.
         if (toKeysetId) {
           this.keyset = toKeysetId;
           this.querySelector('#' + this.layout + '-' + this.keyset).nextKeyset =
               detail.nextKeyset;
         }
         var toLayoutId = detail.toLayout;
         // Layout transition key.
         if (toLayoutId)
           this.layout = toLayoutId;
         var char = detail.char;
         if (enterUpperOnSpace) {
           enterUpperOnSpace = false;
           if (char == ' ')
             this.keyset = 'upper';
         }
         switch(char) {
           case 'Invalid':
             swipeStatus.swipeFlags = 0;
             return;
           case 'Shift':
             swipeStatus.swipeFlags = 0;
-            // We have reverted to lower case.
-            if(this.classList.contains('caps-locked'))
-              this.classList.remove('caps-locked');
             return;
           case 'Microphone':
             this.voiceInput_.onDown();
             return;
           case '.':
           case '?':
           case '!':
             enterUpperOnSpace = true;
             break;
           default:
@@ skipping 12 matching lines @@
        * @param {Object} detail The detail of pressed key.
        */
       keyLongpress: function(event, detail) {
         // If the gesture is long press, remove the pointermove listener.
         this.removeEventListener('pointermove', this.swipeHandler, false);
         var toKeyset = detail.toKeyset;
         // Keyset transtion key.
         if (toKeyset) {
           this.keyset = toKeyset;
           this.querySelector('#' + this.layout + '-' + this.keyset).nextKeyset =
               detail.nextKeyset;

[bshe, 2013/09/16 17:52:01]

nit: accidentally removed the empty line?

[rsadam, 2013/09/16 18:23:49]

Done.

-
           // Locks the keyset before removing active to prevent flicker.
           this.classList.add('caps-locked');
           // Makes last pressed key inactive if transit to a new keyset on long
           // press.
           this.lastPressedKey.classList.remove('active');
         }
       },
 
       /**
        * Handles a change in the keyboard layout. Auto-selects the default
@@ skipping 75 matching lines @@
           }
         }
         if (keysetsLoaded)
           console.error('No default keyset found for ' + this.layout);
         return false;
       }
     });
   </script>
 </polymer-element>