Modernization + AZStd::function compare fix. (#3680)

* Modernization + small fix.

Modernize ( `bool`/`override`/other) code in AzCore, AzFramework, AzQtComponents, AzToolsFramework, etc.
Replaced a `bind` or two, use `using` in a few places as well.

Fix nullptr comparison of AZStd::function.

Signed-off-by: nemerle <96597+nemerle@users.noreply.github.com>

* Apply review-based changes

Signed-off-by: nemerle <96597+nemerle@users.noreply.github.com>

Code/Framework/AzQtComponents/AzQtComponents/Components/DockTabBar.cpp

@@ -147,7 +147,7 @@ namespace AzQtComponents
         TabBar::tabLayoutChange();
 
         // Only the active tab's close button should be shown
-        const ButtonPosition closeSide = (ButtonPosition)style()->styleHint(QStyle::SH_TabBar_CloseButtonPosition, 0, this);
+        const ButtonPosition closeSide = (ButtonPosition)style()->styleHint(QStyle::SH_TabBar_CloseButtonPosition, nullptr, this);
         const int numTabs = count();
         const int activeTabIndex = currentIndex();
         for (int i = 0; i < numTabs; ++i)
@@ -190,7 +190,7 @@ namespace AzQtComponents
             }
         });
 
-        const ButtonPosition closeSide = (ButtonPosition) style()->styleHint(QStyle::SH_TabBar_CloseButtonPosition, 0, this);
+        const ButtonPosition closeSide = (ButtonPosition) style()->styleHint(QStyle::SH_TabBar_CloseButtonPosition, nullptr, this);
         setTabButton(index, closeSide, closeButton);
     }
 

Code/Framework/AzQtComponents/AzQtComponents/Components/FlowLayout.cpp

@@ -112,7 +112,7 @@ QLayoutItem* FlowLayout::takeAt(int index)
     }
     else
     {
-        return 0;
+        return nullptr;
     }
 }
 
@@ -207,7 +207,7 @@ int FlowLayout::smartSpacing(QStyle::PixelMetric pm) const
     else if (parent->isWidgetType())
     {
         QWidget* pw = static_cast<QWidget*>(parent);
-        return pw->style()->pixelMetric(pm, 0, pw);
+        return pw->style()->pixelMetric(pm, nullptr, pw);
     }
     else
     {

Code/Framework/AzQtComponents/AzQtComponents/Components/StyledSpinBox.cpp

@@ -75,11 +75,11 @@ namespace AzQtComponents
                 connect(slider, &QSlider::sliderReleased, this, [this] { m_dragging = false; });
             }
         }
-        ~ClickEventFilterPrivate() {}
+        ~ClickEventFilterPrivate() override {}
     signals:
         void clickOnApplication(const QPoint& pos);
     protected:
-        bool eventFilter(QObject* obj, QEvent* event)
+        bool eventFilter(QObject* obj, QEvent* event) override
         {
             if (event->type() == QEvent::MouseButtonRelease && !m_dragging)
             {

Code/Framework/AzQtComponents/AzQtComponents/Components/Widgets/LineEdit.cpp

@@ -773,7 +773,7 @@ namespace AzQtComponents
         if (numButtons > 0)
         {
             // and finally add the right margins QLineEdit removes to make the buttons fit (it thinks)
-            const int iconSize = style->pixelMetric(QStyle::PM_SmallIconSize, 0, widget);
+            const int iconSize = style->pixelMetric(QStyle::PM_SmallIconSize, nullptr, widget);
             const int delta = iconSize / 4 + iconSize + 6;
             r.setRight(r.right() + delta * numButtons);
         }

Code/Framework/AzQtComponents/AzQtComponents/Components/Widgets/ScrollBar.cpp

@@ -191,7 +191,7 @@ namespace AzQtComponents
         };
         QMap<QObject*, ScrollAreaData> m_widgets;
 
-        void perScrollBar(QObject* scrollArea, void (QScrollBar::*callback)(void))
+        void perScrollBar(QObject* scrollArea, void (QScrollBar::*callback)())
         {
             auto iterator = m_widgets.find(scrollArea);
             if (iterator != m_widgets.end())

Code/Framework/AzQtComponents/AzQtComponents/Components/Widgets/TabWidget.cpp

@@ -632,7 +632,7 @@ namespace AzQtComponents
             return;
         }
 
-        ButtonPosition closeSide = (ButtonPosition)style()->styleHint(QStyle::SH_TabBar_CloseButtonPosition, 0, this);
+        ButtonPosition closeSide = (ButtonPosition)style()->styleHint(QStyle::SH_TabBar_CloseButtonPosition, nullptr, this);
         for (int i = 0; i < count(); i++)
         {
             QWidget* tabBtn = tabButton(i, closeSide);

Code/Framework/AzQtComponents/AzQtComponents/PropertyEditorStandalone/main.cpp

@@ -135,7 +135,7 @@ public:
             if (auto editContext = serializeContext->GetEditContext())
             {
                 editContext->Class<SimpleKeyedContainer>("SimpleKeyContainer", "")
-                    ->DataElement(0, &SimpleKeyedContainer::m_map, "map", "")
+                    ->DataElement(nullptr, &SimpleKeyedContainer::m_map, "map", "")
                         ->ElementAttribute(AZ::Edit::Attributes::ShowAsKeyValuePairs, true);
             }
         }

Code/Framework/AzQtComponents/AzQtComponents/Tests/AzQtComponentTests.cpp

@@ -20,7 +20,7 @@ public:
         AzQtComponents::registerMetaTypes();
     }
 
-    virtual ~AzQtComponentsTestEnvironment() {}
+    ~AzQtComponentsTestEnvironment() override {}
 
 protected: