DiffEditor: Fix editor actions

The text editor widgets all need a TextEditorActionHandler that takes
care of the editor actions for them.
Each text editor needs its own context, so the editor with focus
receives the actions. This does not happen automatically for these text
editors, since the diff editor manages these itself.

Task-number: QTCREATORBUG-9445
Change-Id: Ib42f095ec23550e401e8ee9b36f3f49517a22877
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/diffeditor/diffview.cpp

@@ -25,6 +25,7 @@
 
 #include "diffview.h"
 
+#include "diffeditorconstants.h"
 #include "diffeditordocument.h"
 #include "diffeditoricons.h"
 #include "unifieddiffeditorwidget.h"
@@ -90,14 +91,19 @@ void IDiffView::setSyncToolTip(const QString &text)
     m_syncToolTip = text;
 }
 
-UnifiedView::UnifiedView() : m_widget(0)
+UnifiedView::UnifiedView()
 {
-    setId(UNIFIED_VIEW_ID);
+    setId(Constants::UNIFIED_VIEW_ID);
     setIcon(Icons::UNIFIED_DIFF.icon());
     setToolTip(QCoreApplication::translate("DiffEditor::UnifiedView", "Switch to Unified Diff Editor"));
 }
 
 QWidget *UnifiedView::widget()
+{
+    return textEditorWidget();
+}
+
+TextEditor::TextEditorWidget *UnifiedView::textEditorWidget()
 {
     if (!m_widget) {
         m_widget = new UnifiedDiffEditorWidget;
@@ -152,7 +158,7 @@ void UnifiedView::setSync(bool sync)
 
 SideBySideView::SideBySideView() : m_widget(0)
 {
-    setId(SIDE_BY_SIDE_VIEW_ID);
+    setId(Constants::SIDE_BY_SIDE_VIEW_ID);
     setIcon(Icons::SIDEBYSIDE_DIFF.icon());
     setToolTip(QCoreApplication::translate("DiffEditor::SideBySideView",
                                            "Switch to Side By Side Diff Editor"));
@@ -170,6 +176,18 @@ QWidget *SideBySideView::widget()
     return m_widget;
 }
 
+TextEditor::TextEditorWidget *SideBySideView::leftEditorWidget()
+{
+    widget(); // ensure widget creation
+    return m_widget->leftEditorWidget();
+}
+
+TextEditor::TextEditorWidget *SideBySideView::rightEditorWidget()
+{
+    widget(); // ensure widget creation
+    return m_widget->rightEditorWidget();
+}
+
 void SideBySideView::setDocument(DiffEditorDocument *document)
 {
     QTC_ASSERT(m_widget, return);