MDL-33890 Make course blocks less theme dependant

This fix checks that the empty block region is actaually the standard one, so
it can be hidden. The blocks move operating area is not resticted to page
content any more.

lib/yui/blocks/blocks.js

@@ -8,7 +8,6 @@ YUI.add('moodle-core-blocks', function(Y) {
         EDITINGMOVE : 'editing_move',
         HEADER : 'header',
         LIGHTBOX : 'lightbox',
-        PAGECONTENT : 'page-content',
         REGIONCONTENT : 'region-content',
         SKIPBLOCK : 'skip-block',
         SKIPBLOCKTO : 'skip-block-to'
@@ -28,7 +27,8 @@ YUI.add('moodle-core-blocks', function(Y) {
             this.parentnodeclass = CSS.REGIONCONTENT;
 
             // Initialise blocks dragging
-            var blockregionlist = Y.Node.all('#'+CSS.PAGECONTENT+' div.'+CSS.BLOCKREGION);
+            // Find all block regions on the page
+            var blockregionlist = Y.Node.all('div.'+CSS.BLOCKREGION);
 
             if (blockregionlist.size() === 0) {
                 return false;
@@ -84,9 +84,6 @@ YUI.add('moodle-core-blocks', function(Y) {
                         }).plug(Y.Plugin.DDProxy, {
                             // Don't move the node at the end of the drag
                             moveOnEnd: false
-                        }).plug(Y.Plugin.DDConstrained, {
-                            // Keep it inside the .course-content
-                            constrain: '#'+CSS.PAGECONTENT
                         }).plug(Y.Plugin.DDWinScroll);
                     }
                 }, this);
@@ -139,6 +136,10 @@ YUI.add('moodle-core-blocks', function(Y) {
                 return false;
             }
 
+            // TODO: Hiding-displaying block region only works for base theme blocks
+            // (region-pre, region-post) at the moment. It should be improved
+            // to work with custom block regions as well.
+
             // TODO: Fix this for the case when user drag block towards empty section,
             // then the section appears, then user chnages his mind and moving back to
             // original section. The opposite section remains opened and empty.
@@ -151,9 +152,9 @@ YUI.add('moodle-core-blocks', function(Y) {
             }
 
             // Moving from empty region-content towards the opposite one,
-            // hide empty one
+            // hide empty one (only for region-pre, region-post areas at the moment).
             regionname = this.get_region_id(drop.ancestor('div.'+CSS.BLOCKREGION));
-            if (this.dragsourceregion.all('.'+CSS.BLOCK).size() == 0) {
+            if (this.dragsourceregion.all('.'+CSS.BLOCK).size() == 0 && this.dragsourceregion.get('id').match(/(region-pre|region-post)/i)) {
                 if (!documentbody.hasClass('side-'+regionname+'-only')) {
                     documentbody.addClass('side-'+regionname+'-only');
                 }