Minimized windows should not be activated by another user in multiprofile scenario.

ash/shell/shell_delegate_impl.cc

Index: ash/shell/shell_delegate_impl.cc
diff --git a/ash/shell/shell_delegate_impl.cc b/ash/shell/shell_delegate_impl.cc
index 4af993a30e347c5b7a2a1fccc5d72e716b35d299..ce07345dbeb595ddd3c4fd1548a5c85cf17ba39f 100644
--- a/ash/shell/shell_delegate_impl.cc
+++ b/ash/shell/shell_delegate_impl.cc
@@ -89,6 +89,10 @@ class SessionStateDelegateImpl : public SessionStateDelegate {
       aura::Window* window) override {
     return Shell::GetInstance()->delegate()->GetActiveBrowserContext();
   }
+  content::BrowserContext* GetUserPresentingBrowserContextForWindow(
+      aura::Window* window) override {
+    return NULL;
+  }
   int GetMaximumNumberOfLoggedInUsers() const override { return 3; }
   int NumberOfLoggedInUsers() const override {
     // ash_shell has 2 users.