[Mac] Hide all shims when Chrome is hidden.

chrome/browser/app_controller_mac.mm

Index: chrome/browser/app_controller_mac.mm
diff --git a/chrome/browser/app_controller_mac.mm b/chrome/browser/app_controller_mac.mm
index 093610797a5221df83fcbeae9bee1c8465431c5b..f46a18900afc7547575a9e831460b3d222e11862 100644
--- a/chrome/browser/app_controller_mac.mm
+++ b/chrome/browser/app_controller_mac.mm
@@ -367,6 +367,10 @@ class AppControllerProfileObserver : public ProfileInfoCacheObserver {
       MacStartupProfiler::WILL_FINISH_LAUNCHING);
 }
 
+- (void)applicationWillHide:(NSNotification*)notification {
+  apps::ExtensionAppShimHandler::OnChromeWillHide();
+}
+
 - (BOOL)tryToTerminateApplication:(NSApplication*)app {
   // Check for in-process downloads, and prompt the user if they really want
   // to quit (and thus cancel downloads). Only check if we're not already