Do not show notifications when in fullscreen or screensaver mode....

chrome/browser/fullscreen_mac.mm

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "chrome/browser/fullscreen.h"
+
+#import <Carbon/Carbon.h>
+#import <Cocoa/Cocoa.h>
+
+#import "base/logging.h"
+
+@interface FullScreenMonitor : NSObject {
+ @private
+  BOOL fullScreen_;
+  EventHandlerRef eventHandler_;
+}
+
+@property (nonatomic, getter=isFullScreen) BOOL fullScreen;
+
+@end
+
+static OSStatus handleAppEvent(EventHandlerCallRef myHandler,
+                               EventRef event,
+                               void* userData) {
+  DCHECK(userData);
+
+  FullScreenMonitor* fullScreenMonitor =
+      reinterpret_cast<FullScreenMonitor*>(userData);
+
+  UInt32 mode = 0;
+  OSStatus status = GetEventParameter(event,
+                                      kEventParamSystemUIMode,
+                                      typeUInt32,
+                                      NULL,
+                                      sizeof(UInt32),
+                                      NULL,
+                                      &mode);
+  if (status != noErr)
+    return status;
+  BOOL isFullScreenMode = mode == kUIModeAllHidden;
+  [fullScreenMonitor setFullScreen:isFullScreenMode];
+  return noErr;
+}
+
+@implementation FullScreenMonitor
+
+@synthesize fullScreen = fullScreen_;
+
+- (id)init {
+  if ((self = [super init])) {
+    // Check if the user is in presentation mode initially.
+    SystemUIMode currentMode;
+    GetSystemUIMode(&currentMode, NULL);
+    fullScreen_ = currentMode == kUIModeAllHidden;
+
+    // Register a Carbon event to receive the notification about the login
+    // session's UI mode change.
+    EventTypeSpec events[] =
+      {{ kEventClassApplication, kEventAppSystemUIModeChanged }};
+    OSStatus status = InstallApplicationEventHandler(
+        NewEventHandlerUPP(handleAppEvent),
+        GetEventTypeCount(events),
+        events,
+        self,
+        &eventHandler_);
+    if (status) {
+      [self release];
+      self = nil;
+    }
+  }
+  return self;
+}
+
+- (void)dealloc {
+  if (eventHandler_)
+    RemoveEventHandler(eventHandler_);
+  [super dealloc];
+}
+
+@end
+
+static FullScreenMonitor* g_fullScreenMonitor = nil;
+
+void InitFullScreenMonitor() {
+  if (!g_fullScreenMonitor)
+    g_fullScreenMonitor = [[FullScreenMonitor alloc] init];
+}
+
+void StopFullScreenMonitor() {
+  [g_fullScreenMonitor release];
+  g_fullScreenMonitor = nil;
+}
+
+bool IsFullScreenMode() {
+  // Check if the main display has been captured (game in particular).
+  if (CGDisplayIsCaptured(CGMainDisplayID()))
+    return true;
+
+  return [g_fullScreenMonitor isFullScreen];
+}