Core: Show document icons the "Open Documents" view

Having the document icon looks more natural than having just the text
of the document.

Change-Id: I7cb6fda6b4241c0d124c18c3c74dc4a1e614b02d
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/coreplugin/editormanager/openeditorsview.cpp

@@ -30,6 +30,7 @@
 
 #include <coreplugin/actionmanager/actionmanager.h>
 #include <coreplugin/actionmanager/command.h>
+#include <utils/fsengine/fileiconprovider.h>
 #include <utils/qtcassert.h>
 
 #include <QApplication>
@@ -223,6 +224,16 @@ void ProxyModel::setSourceModel(QAbstractItemModel *sm)
     }
 }
 
+QVariant ProxyModel::data(const QModelIndex &index, int role) const
+{
+    if (role == Qt::DecorationRole && index.column() == 0) {
+        const QString fileName = QAbstractProxyModel::data(index, Qt::DisplayRole).toString();
+        return Utils::FileIconProvider::icon(Utils::FilePath::fromString(fileName));
+    }
+
+    return QAbstractProxyModel::data(index, role);
+}
+
 QModelIndex ProxyModel::sibling(int row, int column, const QModelIndex &idx) const
 {
     return QAbstractItemModel::sibling(row, column, idx);

src/plugins/coreplugin/editormanager/openeditorsview.h

@@ -50,6 +50,8 @@ public:
 
     void setSourceModel(QAbstractItemModel *sourceModel) override;
 
+    QVariant data(const QModelIndex &index, int role) const override;
+
     // QAbstractProxyModel::sibling is broken in Qt 5
     QModelIndex sibling(int row, int column, const QModelIndex &idx) const override;
     // QAbstractProxyModel::supportedDragActions delegation is missing in Qt 5