[Mac] A more robust way to ensure panels avoid key status on window close

chrome/browser/ui/cocoa/panels/panel_cocoa_browsertest.mm

Index: chrome/browser/ui/cocoa/panels/panel_cocoa_browsertest.mm
diff --git a/chrome/browser/ui/cocoa/panels/panel_cocoa_browsertest.mm b/chrome/browser/ui/cocoa/panels/panel_cocoa_browsertest.mm
index 6f8cc1c2d16c24b1b7a76d762517f7a1795339a7..d0c82bd2a2efb45a181550f0fb4c6bc7bd4fafd3 100644
--- a/chrome/browser/ui/cocoa/panels/panel_cocoa_browsertest.mm
+++ b/chrome/browser/ui/cocoa/panels/panel_cocoa_browsertest.mm
@@ -4,14 +4,71 @@
 
 #import <Cocoa/Cocoa.h>
 
+#import "base/mac/scoped_nsobject.h"
+#include "base/run_loop.h"
+#include "base/test/test_timeouts.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/ui/browser_commands.h"
 #include "chrome/browser/ui/browser_finder.h"
+#include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/panels/base_panel_browser_test.h"
 #include "chrome/browser/ui/panels/panel.h"
 #include "content/public/test/test_utils.h"
 
+// Class that spins a run loop until an NSWindow gains key status.
+@interface CocoaActivationWaiter : NSObject {
+ @private
+  base::RunLoop* runLoop_;
+  BOOL observed_;
+}
+
+- (id)initWithWindow:(NSWindow*)window;
+- (void)windowDidBecomeKey:(NSNotification*)notification;
+- (BOOL)waitUntilActive;
+
+@end
+
+@implementation CocoaActivationWaiter
+
+- (id)initWithWindow:(NSWindow*)window {
+  EXPECT_FALSE([window isKeyWindow]);
+  if ((self = [super init])) {
+    [[NSNotificationCenter defaultCenter]
+        addObserver:self
+           selector:@selector(windowDidBecomeKey:)
+               name:NSWindowDidBecomeKeyNotification
+             object:window];
+  }
+  return self;
+}
+
+- (void)dealloc {
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+  [super dealloc];
+}
+
+- (void)windowDidBecomeKey:(NSNotification*)notification {
+  observed_ = YES;
+  if (runLoop_)
+    runLoop_->Quit();
+}
+
+- (BOOL)waitUntilActive {
+  if (observed_)
+    return YES;
+
+  base::RunLoop runLoop;
+  base::MessageLoop::current()->task_runner()->PostDelayedTask(
+      FROM_HERE, runLoop.QuitClosure(), TestTimeouts::action_timeout());
+  runLoop_ = &runLoop;
+  runLoop.Run();
+  runLoop_ = nullptr;
+  return observed_;
+}
+
+@end
+
 typedef BasePanelBrowserTest PanelCocoaBrowserTest;
 
 IN_PROC_BROWSER_TEST_F(PanelCocoaBrowserTest, MenuItems) {
@@ -83,3 +140,39 @@ IN_PROC_BROWSER_TEST_F(PanelCocoaBrowserTest, MenuItems) {
 
   panel->Close();
 }
+
+// Test that panels do not become active when closing a window, even when a
+// panel is otherwise the topmost window.
+IN_PROC_BROWSER_TEST_F(PanelCocoaBrowserTest, InactivePanelsNotActivated) {
+  // Note CreateDockedPanel() sets wait_for_fully_created and SHOW_AS_ACTIVE,
+  // so the following spins a run loop until the respective panel is activated.
+  Panel* docked_panel_1 = CreateDockedPanel("Panel1", gfx::Rect());
+  EXPECT_TRUE([docked_panel_1->GetNativeWindow() isKeyWindow]);
+
+  // Activate the browser. Otherwise closing the second panel will correctly
+  // raise the first panel since panels are allowed to become key if they were
+  // actually the most recently focused window (as opposed to being merely the
+  // topmost window on the z-order stack).
+  NSWindow* browser_window = browser()->window()->GetNativeWindow();
+  base::scoped_nsobject<CocoaActivationWaiter> waiter(
+      [[CocoaActivationWaiter alloc] initWithWindow:browser_window]);
+  browser()->window()->Activate();
+  EXPECT_TRUE([waiter waitUntilActive]);
+
+  // Creating a second panel will activate it (and make it topmost).
+  Panel* docked_panel_2 = CreateDockedPanel("Panel2", gfx::Rect());
+  EXPECT_TRUE([docked_panel_2->GetNativeWindow() isKeyWindow]);
+
+  // Verify the assumptions that the panels are actually topmost.
+  EXPECT_EQ(docked_panel_2->GetNativeWindow(),
+            [[NSApp orderedWindows] objectAtIndex:0]);
+  EXPECT_EQ(docked_panel_1->GetNativeWindow(),
+            [[NSApp orderedWindows] objectAtIndex:1]);
+
+  // Close the second panel and wait for the browser to become active.
+  waiter.reset([[CocoaActivationWaiter alloc] initWithWindow:browser_window]);
+  docked_panel_2->Close();
+
+  EXPECT_TRUE([waiter waitUntilActive]);
+  EXPECT_TRUE([browser_window isKeyWindow]);
+}