Add 'Copy message' context menu item for EventSource messages.

This CL adds a "Copy message" context menu item for EventSource messages in the DevTools network panel. This context menu item copies the data from the selected EventSource message.

Bug: 1111375
Change-Id: I1b531badfbc2417612a2500482bd8cd772bcfb4e
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2329393
Reviewed-by: Jan Scheffler <janscheffler@chromium.org>
Commit-Queue: Jan Scheffler <janscheffler@chromium.org>

front_end/network/EventSourceMessagesView.js

@@ -7,6 +7,7 @@
 
 import * as Common from '../common/common.js';
 import * as DataGrid from '../data_grid/data_grid.js';
+import * as Host from '../host/host.js';
 import * as SDK from '../sdk/sdk.js';
 import * as UI from '../ui/ui.js';
 
@@ -33,6 +34,7 @@ export class EventSourceMessagesView extends UI.Widget.VBox {
     this._dataGrid = new DataGrid.SortableDataGrid.SortableDataGrid({displayName: ls`Event Source`, columns});
     this._dataGrid.setStriped(true);
     this._dataGrid.setStickToBottom(true);
+    this._dataGrid.setRowContextMenuCallback(this._onRowContextMenu.bind(this));
     this._dataGrid.markColumnAsSortedBy('time', DataGrid.DataGrid.Order.Ascending);
     this._sortItems();
     this._dataGrid.addEventListener(DataGrid.DataGrid.Events.SortingChanged, this._sortItems, this);
@@ -80,6 +82,17 @@ export class EventSourceMessagesView extends UI.Widget.VBox {
     }
     this._dataGrid.sortNodes(comparator, !this._dataGrid.isSortOrderAscending());
   }
+
+  /**
+   * @param {!UI.ContextMenu.ContextMenu} contextMenu
+   * @param {!DataGrid.DataGrid.DataGridNode<!EventSourceMessageNode>} node
+   */
+  _onRowContextMenu(contextMenu, node) {
+    contextMenu.clipboardSection().appendItem(
+        Common.UIString.UIString('Copy message'),
+        Host.InspectorFrontendHost.InspectorFrontendHostInstance.copyText.bind(
+            Host.InspectorFrontendHost.InspectorFrontendHostInstance, node.data.data));
+  }
 }
 
 /**