Fix context of Locator input

- In the main window, the locator input (actually the status bar)
  visually feels like being part of the mode widget, so give
  it its context.
- In extra editor windows, the whole editor window should have
  "editor manager" context, so that is also active for the locator
  input.

Task-number: QTCREATORBUG-20626
Task-number: QTCREATORBUG-20071
Change-Id: Ib68d6a8177446572ea59c3cc057eca0706173e11
Reviewed-by: Xing Xiong
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/coreplugin/statusbarmanager.cpp

@@ -25,8 +25,10 @@
 
 #include "statusbarmanager.h"
 
+#include "imode.h"
 #include "mainwindow.h"
 #include "minisplitter.h"
+#include "modemanager.h"
 
 #include <utils/qtcassert.h>
 
@@ -45,6 +47,17 @@ static QPointer<QSplitter> m_splitter;
 static QList<QPointer<QWidget>> m_statusBarWidgets;
 static QList<QPointer<IContext>> m_contexts;
 
+/*!
+    Context that always returns the context of the active's mode widget (if available).
+*/
+class StatusBarContext : public IContext
+{
+public:
+    StatusBarContext(QObject *parent);
+
+    Context context() const final;
+};
+
 static QWidget *createWidget(QWidget *parent)
 {
     QWidget *w = new QWidget(parent);
@@ -85,6 +98,10 @@ static void createStatusBarManager()
     bar->insertPermanentWidget(1, rightCornerWidget);
     m_statusBarWidgets.append(rightCornerWidget);
 
+    auto context = new StatusBarContext(bar);
+    context->setWidget(bar);
+    ICore::addContextObject(context);
+
     QObject::connect(ICore::instance(), &ICore::saveSettingsRequested, [] {
         QSettings *s = ICore::settings();
         s->beginGroup(QLatin1String(kSettingsGroup));
@@ -152,4 +169,20 @@ void StatusBarManager::restoreSettings()
     m_splitter->setSizes(QList<int>() << leftSplitWidth << (sum - leftSplitWidth));
 }
 
+StatusBarContext::StatusBarContext(QObject *parent)
+    : IContext(parent)
+{
+}
+
+Context StatusBarContext::context() const
+{
+    IMode *currentMode = ModeManager::currentMode();
+    QWidget *modeWidget = currentMode ? currentMode->widget() : nullptr;
+    if (modeWidget) {
+        if (IContext *context = ICore::contextObject(modeWidget))
+            return context->context();
+    }
+    return Context();
+}
+
 } // Core