Move content shell context menu to ShellWebContentsViewDelegate in Views

content/shell/browser/shell_mac.mm

Index: content/shell/browser/shell_mac.mm
diff --git a/content/shell/browser/shell_mac.mm b/content/shell/browser/shell_mac.mm
index e33138f4a668f58d4fb16e48e3d7844dfba2d29e..fc972c4c441b8ac1380b88d2347c363e696f34ac 100644
--- a/content/shell/browser/shell_mac.mm
+++ b/content/shell/browser/shell_mac.mm
@@ -274,11 +274,6 @@ void Shell::PlatformSetTitle(const base::string16& title) {
   [window_ setTitle:title_string];
 }
 
-bool Shell::PlatformHandleContextMenu(
-    const content::ContextMenuParams& params) {
-  return false;
-}
-
 void Shell::Close() {
   if (headless_)
     delete this;