Add launcherPage.hide() API.

chrome/browser/ui/app_list/app_list_service.h

Index: chrome/browser/ui/app_list/app_list_service.h
diff --git a/chrome/browser/ui/app_list/app_list_service.h b/chrome/browser/ui/app_list/app_list_service.h
index b8dafd3be32333c6a52cb19002f6a456834aa109..421b0c14591bd68b9d731a1bd184db1343119df9 100644
--- a/chrome/browser/ui/app_list/app_list_service.h
+++ b/chrome/browser/ui/app_list/app_list_service.h
@@ -100,6 +100,10 @@ class AppListService {
   // Shows the app list, and switches to the custom launcher page.
   virtual void ShowForCustomLauncherPage(Profile* profile) = 0;
 
+  // Hides the custom launcher page if it is currently being shown. Does nothing
+  // otherwise.
+  virtual void HideLauncherPageIfShowing() = 0;

[Matt Giuca, 2015/05/14 06:56:02]

I think the "IfShowing" is not necessary (it's sort of an obvious consequence
that if the launcher page is hidden, hide can't do anything). Worth documenting,
but unnecessary in the name.

[calamity, 2015/05/14 08:11:27]

Done. Also changed to Hide_Custom_LauncherPage() for consistency.

+
   // Dismiss the app list.
   virtual void DismissAppList() = 0;