Added persistent capitalization to the Virtual Keyboard.

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">
@@ skipping 32 matching lines @@
     var REPEAT_INTERVAL_MSEC = 50;
 
     /**
      * The double click/tap interval.
      * @const
      * @type {number}
      */
     var DBL_INTERVAL_MSEC = 300;
 
     /**
+     * The index of the name of the keyset when searching for all keysets.
+     * @const
+     * @type {number}
+     */
+    var REGEX_KEYSET_INDEX = 1;
+
+    /**
+     * The integer number of matches when searching for keysets.
+     * @const
+     * @type {number}
+     */
+    var REGEX_MATCH_COUNT = 2;
+
+    /**
      * The boolean to decide if keyboard should transit to upper case keyset
      * when spacebar is pressed. If a closing punctuation is followed by a
      * spacebar, keyboard should automatically transit to upper case.
      * @type {boolean}
      */
     var enterUpperOnSpace = false;
 
     /**
      * A structure to track the currently repeating key on the keyboard.
      */
@@ skipping 116 matching lines @@
       dblTimer_: null,
       swipeHandler: null,
 
       /**
       * Handles the state of the shift key.
       */
       keysetChanged: function() {
         var keysetId = '#' + this.layout + '-' + this.keyset;
         var keyset = this.querySelector(keysetId);
 
-        // Unlocks the keyboard if the current keyset is not lockable.
-        if (!keyset.getAttribute('lockable'))
-          this.classList.remove('locked');
+        // Capitalizes keyboard if capslock is enabled but we are in the lower
+        // keyset.

[bshe, 2013/08/30 15:33:16]

Could you rephrase this comment? Not all keyboard has lower keyset.
Something like "If capslock is enabled and capsLockTo is not null, redirect to
keyset specified by capsLockTo" maybe better.

+        if (this.classList.contains('shift-locked') && keyset.shiftLocksTo)

[bshe, 2013/08/30 15:33:16]

Any particular reason not use caps-locked and capLockTo? It sounds easier to
understand.

+          this.keyset = keyset.shiftLocksTo; 
         
       },
 
       ready: function() {
         this.voiceInput_ = new VoiceInput(this);
         this.swipeHandler = this.onSwipeUpdate.bind(this);
       },
 
       /**
        * When double click/tap event is enabled, the second key-down and key-up
@@ skipping 139 matching lines @@
       up: function(event) {
         if (this.dblDetail_) {
           this.dblDetail_.clickCount++;
           if (this.dblDetail_.clickCount == 2) {
             this.keyset = this.dblDetail_.toKeyset;
             var keysetId = '#' + this.layout + '-' + this.keyset;
             var keyset = this.querySelector(keysetId);
             keyset.nextKeyset = this.dblTimer_.nextKeyset;
             clearTimeout(this.dblTimer_);
             
-            // Checks if shift is capitalized.
-            if (keyset.getAttribute('lockable'))
-              this.classList.add('locked');
+            this.classList.add('shift-locked');
 
             this.dblDetail_ = null;
           }
         }
 
         // TODO(zyaozhujun): There are some edge cases to deal with later.
         // (for instance, what if a second finger trigger a down and up
         // event sequence while swiping).
         // When pointer up from the screen, a swipe selection session finished,
         // all the data should be reset to prepare for the next session.
@@ skipping 14 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 toKeyset = detail.toKeyset;
+        var toKeysetId = detail.toKeyset;
         // Keyset transition key.
-        if (toKeyset) {
-          this.keyset = toKeyset;
+        if (toKeysetId) {
+          this.keyset = toKeysetId;
           this.querySelector('#' + this.layout + '-' + this.keyset).nextKeyset =
               detail.nextKeyset;
         }
-        var toLayout = detail.toLayout;
+        var toLayoutId = detail.toLayout;
         // Layout transition key.
-        if (toLayout)
-          this.layout = toLayout;
+        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('shift-locked'))
+              this.classList.remove('shift-locked');
             return;
           case 'Microphone':
             this.voiceInput_.onDown();
             return;
           case '.':
           case '?':
           case '!':
             enterUpperOnSpace = true;
             break;
           default:
@@ skipping 12 matching lines @@
         // 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;
 
           // Locks the keyset before removing active to prevent flicker.
-          this.classList.add('locked');
+          this.classList.add('shift-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
        * keyset for the new layout.
        */
@@ skipping 15 matching lines @@
        * @return {boolean} True if successful. This method can fail if the
        *     keysets corresponding to the layout have not been injected.
        */
       selectDefaultKeyset: function() {
         var keysets = this.querySelectorAll('kb-keyset');
         // Full name of the keyset is of the form 'layout-keyset'.
         var regex = new RegExp('^' + this.layout + '-(.+)');
         var keysetsLoaded = false;
         for (var i = 0; i < keysets.length; i++) {
           var matches = keysets[i].id.match(regex);
-          if (matches && matches.length == 2) {
+          if (matches && matches.length == REGEX_MATCH_COUNT) {
              keysetsLoaded = true;
              if (keysets[i].isDefault) {
-               this.keyset = matches[1];
+               this.keyset = matches[REGEX_KEYSET_INDEX];
                return true;
              }
           }
         }
         if (keysetsLoaded)
           console.error('No default keyset found for ' + this.layout);
         return false;
       }
     });
   </script>
 </polymer-element>