Extend hover area for address bar's bookmark button over bookmarks bar and tab bar (#2020)

Task/Issue URL: https://app.asana.com/0/1177771139624306/1203066850737780/f

Description:
This change removes MouseOverView from NavigationBarVC that was used to display bookmark button
in the address bar. It's replaced with tracking mouse events in MainView. If a mouse is moved in the area
inside the app window but above webView, the bookmark button is shown, otherwise it's hidden.
This way the bookmark button will also be shown when the cursor is over the bookmarks bar and over
the window title bar.

Author: ayoy

DuckDuckGo/MainWindow/MainView.swift

@@ -17,8 +17,93 @@
 //
 
 import Cocoa
+import Combine
 
 final class MainView: NSView {
+    let tabBarContainerView = NSView()
+    let navigationBarContainerView = NSView()
+    let webContainerView = NSView()
+    let findInPageContainerView = NSView().hidden()
+    let bookmarksBarContainerView = NSView()
+    let fireContainerView = NSView()
+    let divider = ColorView(frame: .zero, backgroundColor: .separatorColor)
+
+    private(set) var navigationBarTopConstraint: NSLayoutConstraint!
+    private(set) var addressBarHeightConstraint: NSLayoutConstraint!
+    private(set) var bookmarksBarHeightConstraint: NSLayoutConstraint!
+
+    @Published var isMouseAboveWebView: Bool = false
+
+    override init(frame frameRect: NSRect) {
+        super.init(frame: frameRect)
+
+        for subview in [
+            tabBarContainerView,
+            divider,
+            bookmarksBarContainerView,
+            navigationBarContainerView,
+            webContainerView,
+            findInPageContainerView,
+            fireContainerView,
+        ] {
+            subview.translatesAutoresizingMaskIntoConstraints = false
+            addSubview(subview)
+        }
+
+        addConstraints()
+    }
+
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    private func addConstraints() {
+        bookmarksBarHeightConstraint = bookmarksBarContainerView.heightAnchor.constraint(equalToConstant: 34)
+
+        navigationBarTopConstraint = navigationBarContainerView.topAnchor.constraint(equalTo: topAnchor, constant: 38)
+        addressBarHeightConstraint = navigationBarContainerView.heightAnchor.constraint(equalToConstant: 42)
+
+        NSLayoutConstraint.activate([
+            tabBarContainerView.topAnchor.constraint(equalTo: topAnchor),
+            tabBarContainerView.leadingAnchor.constraint(equalTo: leadingAnchor),
+            tabBarContainerView.trailingAnchor.constraint(equalTo: trailingAnchor),
+            tabBarContainerView.heightAnchor.constraint(equalToConstant: 38),
+
+            divider.topAnchor.constraint(equalTo: navigationBarContainerView.bottomAnchor),
+            divider.leadingAnchor.constraint(equalTo: leadingAnchor),
+            divider.trailingAnchor.constraint(equalTo: trailingAnchor),
+            divider.heightAnchor.constraint(equalToConstant: 1),
+
+            bookmarksBarContainerView.topAnchor.constraint(equalTo: divider.bottomAnchor),
+            bookmarksBarContainerView.leadingAnchor.constraint(equalTo: leadingAnchor),
+            bookmarksBarContainerView.trailingAnchor.constraint(equalTo: trailingAnchor),
+            bookmarksBarHeightConstraint,
+
+            navigationBarTopConstraint,
+            navigationBarContainerView.leadingAnchor.constraint(equalTo: leadingAnchor),
+            navigationBarContainerView.trailingAnchor.constraint(equalTo: trailingAnchor),
+            addressBarHeightConstraint,
+
+            webContainerView.topAnchor.constraint(equalTo: bookmarksBarContainerView.bottomAnchor),
+            webContainerView.bottomAnchor.constraint(equalTo: bottomAnchor),
+            webContainerView.leadingAnchor.constraint(equalTo: leadingAnchor),
+            webContainerView.trailingAnchor.constraint(equalTo: trailingAnchor),
+            webContainerView.widthAnchor.constraint(greaterThanOrEqualToConstant: 512),
+            webContainerView.heightAnchor.constraint(greaterThanOrEqualToConstant: 178),
+
+            findInPageContainerView.topAnchor.constraint(equalTo: bookmarksBarContainerView.bottomAnchor, constant: -4),
+            findInPageContainerView.topAnchor.constraint(equalTo: navigationBarContainerView.bottomAnchor, constant: -4).priority(900),
+            findInPageContainerView.centerXAnchor.constraint(equalTo: navigationBarContainerView.centerXAnchor),
+            findInPageContainerView.widthAnchor.constraint(equalToConstant: 400),
+            findInPageContainerView.heightAnchor.constraint(equalToConstant: 40),
+
+            fireContainerView.topAnchor.constraint(equalTo: topAnchor),
+            fireContainerView.bottomAnchor.constraint(equalTo: bottomAnchor),
+            fireContainerView.leadingAnchor.constraint(equalTo: leadingAnchor),
+            fireContainerView.trailingAnchor.constraint(equalTo: trailingAnchor),
+        ])
+    }
+
     private typealias CFWebServicesCopyProviderInfoType = @convention(c) (CFString, UnsafeRawPointer?) -> NSDictionary?
 
     // PDF Plugin context menu
@@ -47,7 +132,7 @@ final class MainView: NSView {
         }
     }
 
-    // MARK: NSDraggingDestination
+    // MARK: - NSDraggingDestination
 
     override func draggingEntered(_ draggingInfo: NSDraggingInfo) -> NSDragOperation {
         return (nextResponder as? NSDraggingDestination)?.draggingEntered?(draggingInfo) ?? .none
@@ -61,4 +146,50 @@ final class MainView: NSView {
         return (nextResponder as? NSDraggingDestination)?.performDragOperation?(draggingInfo) ?? false
     }
 
+    // MARK: - Mouse Tracking
+
+    func setMouseAboveWebViewTrackingAreaEnabled(_ isEnabled: Bool) {
+        if isEnabled {
+            let trackingArea = makeMouseAboveViewTrackingArea()
+            addTrackingArea(trackingArea)
+            mouseAboveWebViewTrackingArea = trackingArea
+        } else if let mouseAboveWebViewTrackingArea {
+            removeTrackingArea(mouseAboveWebViewTrackingArea)
+            self.mouseAboveWebViewTrackingArea = nil
+            isMouseAboveWebView = false
+        }
+    }
+
+    override func updateTrackingAreas() {
+        if let mouseAboveWebViewTrackingArea {
+            removeTrackingArea(mouseAboveWebViewTrackingArea)
+            isMouseAboveWebView = false
+            let trackingArea = makeMouseAboveViewTrackingArea()
+            self.mouseAboveWebViewTrackingArea = trackingArea
+            addTrackingArea(trackingArea)
+        }
+        super.updateTrackingAreas()
+    }
+
+    override func mouseEntered(with event: NSEvent) {
+        if let mouseAboveWebViewTrackingArea, event.trackingArea == mouseAboveWebViewTrackingArea {
+            isMouseAboveWebView = true
+        }
+    }
+
+    override func mouseExited(with event: NSEvent) {
+        if let mouseAboveWebViewTrackingArea, event.trackingArea == mouseAboveWebViewTrackingArea {
+            isMouseAboveWebView = false
+        }
+    }
+
+    private func makeMouseAboveViewTrackingArea() -> NSTrackingArea {
+        var bounds = bounds
+        bounds.size.height -= webContainerView.bounds.maxY
+        bounds.origin.y += webContainerView.bounds.maxY
+        return NSTrackingArea(rect: bounds, options: [.activeAlways, .mouseEnteredAndExited], owner: self, userInfo: nil)
+    }
+
+    private var mouseAboveWebViewTrackingArea: NSTrackingArea?
+
 }