fix: make BrowserWindow#isFocused() return false when blur() is called on macOS (#33734)

The isFocused() method on macOS works by checking if the selected
BrowserWindow is a key window. Unfortunately, this didn't work well
with blur() because it wasn't calling any macOS APIs that would change
the key status of the window. Hence, this changes the implementation of
blur() to call orderOut first, which removes the key
status of the window. Then when the orderBack function is called, it
moves the window to the back of its level in the screen list, without
changing the key window.

Fixes: https://github.com/electron/electron/issues/33732
Signed-off-by: Darshan Sen <raisinten@gmail.com>

shell/browser/native_window_mac.mm

@@ -507,6 +507,7 @@ void NativeWindowMac::Focus(bool focus) {
     [[NSApplication sharedApplication] activateIgnoringOtherApps:NO];
     [window_ makeKeyAndOrderFront:nil];
   } else {
+    [window_ orderOut:nil];
     [window_ orderBack:nil];
   }
 }

spec-main/api-browser-window-spec.ts

@@ -760,13 +760,137 @@ describe('BrowserWindow module', () => {
         w.focus();
         expect(w.isVisible()).to.equal(false);
       });
+
+      ifit(process.platform !== 'win32')('focuses a blurred window', async () => {
+        {
+          const isBlurred = emittedOnce(w, 'blur');
+          const isShown = emittedOnce(w, 'show');
+          w.show();
+          w.blur();
+          await isShown;
+          await isBlurred;
+        }
+        expect(w.isFocused()).to.equal(false);
+        w.focus();
+        expect(w.isFocused()).to.equal(true);
+      });
+
+      ifit(process.platform !== 'linux')('acquires focus status from the other windows', async () => {
+        const w1 = new BrowserWindow({ show: false });
+        const w2 = new BrowserWindow({ show: false });
+        const w3 = new BrowserWindow({ show: false });
+        {
+          const isFocused3 = emittedOnce(w3, 'focus');
+          const isShown1 = emittedOnce(w1, 'show');
+          const isShown2 = emittedOnce(w2, 'show');
+          const isShown3 = emittedOnce(w3, 'show');
+          w1.show();
+          w2.show();
+          w3.show();
+          await isShown1;
+          await isShown2;
+          await isShown3;
+          await isFocused3;
+        }
+        // TODO(RaisinTen): Investigate why this assertion fails only on Linux.
+        expect(w1.isFocused()).to.equal(false);
+        expect(w2.isFocused()).to.equal(false);
+        expect(w3.isFocused()).to.equal(true);
+
+        w1.focus();
+        expect(w1.isFocused()).to.equal(true);
+        expect(w2.isFocused()).to.equal(false);
+        expect(w3.isFocused()).to.equal(false);
+
+        w2.focus();
+        expect(w1.isFocused()).to.equal(false);
+        expect(w2.isFocused()).to.equal(true);
+        expect(w3.isFocused()).to.equal(false);
+
+        w3.focus();
+        expect(w1.isFocused()).to.equal(false);
+        expect(w2.isFocused()).to.equal(false);
+        expect(w3.isFocused()).to.equal(true);
+
+        {
+          const isClosed1 = emittedOnce(w1, 'closed');
+          const isClosed2 = emittedOnce(w2, 'closed');
+          const isClosed3 = emittedOnce(w3, 'closed');
+          w1.destroy();
+          w2.destroy();
+          w3.destroy();
+          await isClosed1;
+          await isClosed2;
+          await isClosed3;
+        }
+      });
     });
 
-    describe('BrowserWindow.blur()', () => {
+    // TODO(RaisinTen): Make this work on Windows too.
-      it('removes focus from window', () => {
+    // Refs: https://github.com/electron/electron/issues/20464.
+    ifdescribe(process.platform !== 'win32')('BrowserWindow.blur()', () => {
+      it('removes focus from window', async () => {
+        {
+          const isFocused = emittedOnce(w, 'focus');
+          const isShown = emittedOnce(w, 'show');
+          w.show();
+          await isShown;
+          await isFocused;
+        }
+        expect(w.isFocused()).to.equal(true);
         w.blur();
         expect(w.isFocused()).to.equal(false);
       });
+
+      ifit(process.platform !== 'linux')('transfers focus status to the next window', async () => {
+        const w1 = new BrowserWindow({ show: false });
+        const w2 = new BrowserWindow({ show: false });
+        const w3 = new BrowserWindow({ show: false });
+        {
+          const isFocused3 = emittedOnce(w3, 'focus');
+          const isShown1 = emittedOnce(w1, 'show');
+          const isShown2 = emittedOnce(w2, 'show');
+          const isShown3 = emittedOnce(w3, 'show');
+          w1.show();
+          w2.show();
+          w3.show();
+          await isShown1;
+          await isShown2;
+          await isShown3;
+          await isFocused3;
+        }
+        // TODO(RaisinTen): Investigate why this assertion fails only on Linux.
+        expect(w1.isFocused()).to.equal(false);
+        expect(w2.isFocused()).to.equal(false);
+        expect(w3.isFocused()).to.equal(true);
+
+        w3.blur();
+        expect(w1.isFocused()).to.equal(false);
+        expect(w2.isFocused()).to.equal(true);
+        expect(w3.isFocused()).to.equal(false);
+
+        w2.blur();
+        expect(w1.isFocused()).to.equal(true);
+        expect(w2.isFocused()).to.equal(false);
+        expect(w3.isFocused()).to.equal(false);
+
+        w1.blur();
+        expect(w1.isFocused()).to.equal(false);
+        expect(w2.isFocused()).to.equal(false);
+        expect(w3.isFocused()).to.equal(true);
+
+        {
+          const isClosed1 = emittedOnce(w1, 'closed');
+          const isClosed2 = emittedOnce(w2, 'closed');
+          const isClosed3 = emittedOnce(w3, 'closed');
+          w1.destroy();
+          w2.destroy();
+          w3.destroy();
+          await isClosed1;
+          await isClosed2;
+          await isClosed3;
+        }
+      });
     });
 
     describe('BrowserWindow.getFocusedWindow()', () => {