feat: [FC-0070] add message events and styles to the library content page (#35785)

This introduces improvements for XBlock interactions within iframes:

* Add default styles for Library Content that renders in the iframe in the new Studio unit page
* When the `isIframeEmbed` option is enabled, the XBlock sends a `postMessage` to the parent window. When sending such a message, the standard link transition is cancelled and the transition is carried out in the MFE.

cms/djangoapps/contentstore/views/tests/test_block.py

@@ -265,9 +265,10 @@ class GetItemTest(ItemTest):
             html,
             # The instance of the wrapper class will have an auto-generated ID. Allow any
             # characters after wrapper.
-            '"/container/{}" class="action-button">\\s*<span class="action-button-text">View</span>'.format(
-                re.escape(str(wrapper_usage_key))
-            ),
+            (
+                '"/container/{}" class="action-button xblock-view-action-button">'
+                '\\s*<span class="action-button-text">View</span>'
+            ).format(re.escape(str(wrapper_usage_key))),
         )
 
     @patch("cms.djangoapps.contentstore.xblock_storage_handlers.xblock_helpers.get_object_tag_counts")

cms/static/js/views/pages/container.js

@@ -39,6 +39,7 @@ function($, _, Backbone, gettext, BasePage,
             'click .manage-tags-button': 'openManageTags',
             'change .header-library-checkbox': 'toggleLibraryComponent',
             'click .collapse-button': 'collapseXBlock',
+            'click .xblock-view-action-button': 'viewXBlockContent',
         },
 
         options: {
@@ -808,10 +809,6 @@ function($, _, Backbone, gettext, BasePage,
             this.deleteComponent(this.findXBlockElement(event.target));
         },
 
-        createPlaceholderElement: function() {
-            return $('<div/>', {class: 'studio-xblock-wrapper'});
-        },
-
         createComponent: function(template, target) {
             // A placeholder element is created in the correct location for the new xblock
             // and then onNewXBlock will replace it with a rendering of the xblock. Note that
@@ -905,6 +902,26 @@ function($, _, Backbone, gettext, BasePage,
             }
         },
 
+        viewXBlockContent: function(event) {
+          try {
+            if (this.options.isIframeEmbed) {
+              event.preventDefault();
+              var usageId = event.currentTarget.href.split('/').pop() || '';
+              window.parent.postMessage(
+                {
+                  type: 'handleViewXBlockContent',
+                  payload: {
+                    usageId: usageId,
+                  },
+                }, document.referrer
+              );
+              return true;
+            }
+          } catch (e) {
+            console.error(e);
+          }
+        },
+
         toggleSaveButton: function() {
             var $saveButton = $('.nav-actions .save-button');
             if (JSON.stringify(this.selectedLibraryComponents.sort()) === JSON.stringify(this.storedSelectedLibraryComponents.sort())) {

cms/static/sass/course-unit-mfe-iframe-bundle.scss

@@ -1,14 +1,22 @@
 @import 'cms/theme/variables-v1';
 @import 'elements/course-unit-mfe-iframe';
 
+body {
+  min-width: 800px;
+}
+
 .wrapper {
+  .inner-wrapper {
+    max-width: 100%;
+  }
+
   .wrapper-xblock {
     background-color: $transparent;
     border-radius: 6px;
     border: none;
 
     &:hover {
-      border-color: none;
+      border-color: transparent;
     }
 
     .xblock-header-primary {
@@ -23,6 +31,54 @@
       }
     }
 
+    .xblock-header-secondary {
+      border-radius: 0 0 4px 4px;
+
+      .actions-list .action-item .action-button {
+        border-radius: 4px;
+
+        &:hover {
+          background-color: $primary;
+          color: $white;
+        }
+      }
+    }
+
+    &.level-page .xblock-message {
+      padding: ($baseline * .75) ($baseline * 1.2);
+      border-radius: 0 0 4px 4px;
+
+      &.information {
+        color: $text-color;
+        background-color: $xblock-message-info-bg;
+        border-color: $xblock-message-info-border-color;
+      }
+
+      &.validation.has-warnings {
+        color: $black;
+        background-color: $xblock-message-warning-bg;
+        border-color: $xblock-message-warning-border-color;
+        border-top-width: 1px;
+
+        .icon {
+          color: $xblock-message-warning-border-color;
+        }
+      }
+
+      a {
+        color: $primary;
+      }
+    }
+
+    .xblock-author_view-library_content > .wrapper-xblock-message .xblock-message {
+      font-size: 16px;
+      line-height: 22px;
+      border-radius: 4px;
+      padding: ($baseline * 1.2);
+      box-shadow: 0 1px 2px rgba(0, 0, 0, .15), 0 1px 4px rgba(0, 0, 0, .15);
+      margin-bottom: ($baseline * 1.4);
+    }
+
     &.level-element {
       box-shadow: 0 2px 4px rgba(0, 0, 0, .15), 0 2px 8px rgba(0, 0, 0, .15);
       margin: 0 0 ($baseline * 1.4) 0;
@@ -40,28 +96,34 @@
       border-bottom-right-radius: 6px;
     }
 
-    .wrapper-xblock .header-actions .actions-list .action-item .action-button {
-      @extend %button-styles;
-
-      color: $primary;
-
-      .fa-ellipsis-v {
-        font-size: $base-font-size;
+    .wrapper-xblock .header-actions .actions-list {
+      .action-actions-menu:last-of-type .nav-sub {
+        right: 120px;
       }
 
-      &:hover {
-        background-color: $primary;
-        color: $white;
-        border-color: $transparent;
-        color: $white;
-      }
+      .action-item .action-button {
+        @extend %button-styles;
 
-      &:focus {
-        outline: 2px $transparent;
-        background-color: $transparent;
-        box-shadow: inset 0 0 0 2px $primary;
         color: $primary;
-        border-color: $transparent;
+
+        .fa-ellipsis-v {
+          font-size: $base-font-size;
+        }
+
+        &:hover {
+          background-color: $primary;
+          color: $white;
+          border-color: $transparent;
+        color: $white;
+      }
+
+        &:focus {
+          outline: 2px $transparent;
+          background-color: $transparent;
+          box-shadow: inset 0 0 0 2px $primary;
+          color: $primary;
+          border-color: $transparent;
+        }
       }
     }
 
@@ -631,7 +693,7 @@ select {
   }
 }
 
-.xblock-header-primary {
+.xblock-header:not(.xblock-header-library_content, .xblock-header-split_test) .xblock-header-primary {
   position: relative;
 
   &::before {

cms/static/sass/partials/cms/theme/_variables-v1.scss

@@ -315,3 +315,8 @@ $base-font-size: 18px !default;
 $dark: #212529;
 
 $zindex-dropdown: 100;
+
+$xblock-message-info-bg: #eff8fa;
+$xblock-message-info-border-color: #9cd2e6;
+$xblock-message-warning-bg: #fffdf0;
+$xblock-message-warning-border-color: #fff6bf;

cms/templates/studio_xblock_wrapper.html

@@ -229,7 +229,7 @@ upstream_info = UpstreamLink.try_get_for_block(xblock)
             <div class="meta-info">${_('This block contains multiple components.')}</div>
             <ul class="actions-list">
                 <li class="action-item action-view">
-                    <a href="${xblock_url}" class="action-button">
+                    <a href="${xblock_url}" class="action-button xblock-view-action-button">
                         ## Translators: this is a verb describing the action of viewing more details
                         <span class="action-button-text">${('View')}</span>
                         <span class="icon fa fa-arrow-right" aria-hidden="true"></span>