[Mac] Build problems after changing perTab to perWindow

[ltilve]

There are build issues after the last changes applied at 5b4e587 to port at the cocoa part the perWindow approach.

[ltilve]

../../chrome/browser/ui/cocoa/browser_window_cocoa.mm:830:18: error: instance method '-updateSidebarForTabContents:' not found (return type defaults to 'id') [-Werror,-Wobjc-method-access]
[controller_ updateSidebarForTabContents:tab_contents];
^~~~~~~~~~~~~~~~~~~~~~~~~~~

It seems that we need some change as:
+++ b/chrome/browser/ui/cocoa/browser_window_cocoa.mm
@@ -315,7 +315,7 @@ void BrowserWindowCocoa::BookmarkBarStateChanged(
void BrowserWindowCocoa::UpdateDevTools() {
[controller_ updateDevToolsForContents:
browser_->tab_strip_model()->GetActiveWebContents()];

• UpdateSidebarForContents(browser_->tab_strip_model()->GetActiveWebContents());
• UpdateSidebarForContents(browser_->tab_strip_model()->GetActiveWebContents(), nullptr);
  }

or at some other points using [controller_ updateSidebarForContents:tab_contents];

[ryumiel]

Build was fixed at 05463409cb79b88133c7ee6d74bd833fc55abffc
However, we need to change sidebar_controller not to rely on TabContentsController