Compare QIcon QVariants by their cache key

This makes it so that two QVariants created from the same
QIcon (or from QIcons that were assigned one from eachother)
compare to true.
Unfortunately creating two QIcons with the same path and
comparing them still gives false as they have different cacheKeys

Change-Id: Iafe2bc4082a830f9c6469f083c26a7abbe4b35c5
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>

src/gui/kernel/qguivariant.cpp

@@ -164,7 +164,7 @@ public:
 #ifndef QT_NO_ICON
     bool delegate(const QIcon *)
     {
-        return false;
+        return v_cast<QIcon>(Base::m_a)->cacheKey() == v_cast<QIcon>(Base::m_b)->cacheKey();
     }
 #endif
     bool delegate(const void *p) { return Base::delegate(p); }

tests/auto/gui/kernel/qguivariant/test/test.pro

@@ -2,5 +2,6 @@ CONFIG += testcase
 CONFIG += parallel_test
 TARGET = tst_qguivariant
 SOURCES  += tst_qguivariant.cpp
+RESOURCES = tst_qguivariant.qrc
 INCLUDEPATH += $$PWD/../../../../other/qvariant_common
 QT += testlib

tests/auto/gui/kernel/qguivariant/test/tst_qguivariant.cpp

@@ -124,6 +124,8 @@ private slots:
     void implicitConstruction();
 
     void guiVariantAtExit();
+
+    void iconEquality();
 };
 
 void tst_QGuiVariant::constructor_invalid_data()
@@ -702,5 +704,32 @@ void tst_QGuiVariant::guiVariantAtExit()
     QVERIFY(true);
 }
 
+void tst_QGuiVariant::iconEquality()
+{
+    QIcon i;
+    QVariant a = i;
+    QVariant b = i;
+    QCOMPARE(a, b);
+
+    i = QIcon(":/black.png");
+    a = i;
+    QVERIFY(a != b);
+
+    b = a;
+    QCOMPARE(a, b);
+
+    i = QIcon(":/black2.png");
+    a = i;
+    QVERIFY(a != b);
+
+    b = i;
+    QCOMPARE(a, b);
+
+    // This is a "different" QIcon
+    // even if the contents are the same
+    b = QIcon(":/black2.png");
+    QVERIFY(a != b);
+}
+
 QTEST_MAIN(tst_QGuiVariant)
 #include "tst_qguivariant.moc"

tests/auto/gui/kernel/qguivariant/test/tst_qguivariant.qrc

@@ -0,0 +1,6 @@
+<!DOCTYPE RCC><RCC version="1.0">
+<qresource prefix="/">
+<file>black.png</file>
+<file>black2.png</file>
+</qresource>
+</RCC>

tests/auto/widgets/itemviews/qtreewidget/tst_qtreewidget.cpp

@@ -1758,9 +1758,7 @@ void tst_QTreeWidget::setData()
                     QCOMPARE(qvariant_cast<QTreeWidgetItem*>(args.at(0)), item);
                     QCOMPARE(qvariant_cast<int>(args.at(1)), j);
                     item->setIcon(j, icon);
-                    // #### shouldn't cause dataChanged()
-                    QCOMPARE(itemChangedSpy.count(), 1);
-                    itemChangedSpy.clear();
+                    QCOMPARE(itemChangedSpy.count(), 0);
 
                     QString toolTip = QString("toolTip %0").arg(i);
                     item->setToolTip(j, toolTip);