Introduce ui/wm/ directory.

apps/shell/app_shell_browser_main_parts.h

Index: apps/shell/app_shell_browser_main_parts.h
diff --git a/apps/shell/app_shell_browser_main_parts.h b/apps/shell/app_shell_browser_main_parts.h
index bcbfa8fcc6f74d36012c26e98de3b75a396ff45a..b32c715ac326ab027c5427a680bbb879565c1d64 100644
--- a/apps/shell/app_shell_browser_main_parts.h
+++ b/apps/shell/app_shell_browser_main_parts.h
@@ -15,14 +15,14 @@ class ShellBrowserContext;
 struct MainFunctionParams;
 }
 
-namespace shell {
-class MinimalShell;
-}
-
 namespace views {
 class ViewsDelegate;
 }
 
+namespace wm {
+class MinimalShell;
+}
+
 namespace apps {
 
 // Handles initialization of AppShell.
@@ -48,7 +48,7 @@ class AppShellBrowserMainParts : public content::BrowserMainParts {
   scoped_ptr<content::ShellBrowserContext> browser_context_;
 
   // Enable a minimal set of views::corewm to be initialized.
-  scoped_ptr<shell::MinimalShell> minimal_shell_;
+  scoped_ptr<wm::MinimalShell> minimal_shell_;
 
   DISALLOW_COPY_AND_ASSIGN(AppShellBrowserMainParts);
 };