Mac content shell: File > New makes a new browser window.

content/shell/shell_browser_context.h

Index: content/shell/shell_browser_context.h
diff --git a/content/shell/shell_browser_context.h b/content/shell/shell_browser_context.h
index 11220b0fe20c414c6602e9d822f0995f76cff161..5dcf9b14d7633b3ace43a5da5afde3f35d704d78 100644
--- a/content/shell/shell_browser_context.h
+++ b/content/shell/shell_browser_context.h
@@ -10,6 +10,7 @@
 #include "base/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/singleton.h"
 #include "content/public/browser/browser_context.h"
 
 class DownloadManager;
@@ -18,13 +19,11 @@ namespace content {
 
 class DownloadManagerDelegate;
 class ResourceContext;
-class ShellBrowserMainParts;
 class ShellDownloadManagerDelegate;
 
 class ShellBrowserContext : public BrowserContext {
  public:
-  explicit ShellBrowserContext(ShellBrowserMainParts* shell_main_parts);
-  virtual ~ShellBrowserContext();
+  static ShellBrowserContext* GetInstance();
 
   // BrowserContext implementation.
   virtual FilePath GetPath() OVERRIDE;
@@ -43,6 +42,10 @@ class ShellBrowserContext : public BrowserContext {
   virtual quota::SpecialStoragePolicy* GetSpecialStoragePolicy() OVERRIDE;
 
  private:
+  ShellBrowserContext();
+  virtual ~ShellBrowserContext();
+  friend struct DefaultSingletonTraits<ShellBrowserContext>;
+
   // Performs initialization of the ShellBrowserContext while IO is still
   // allowed on the current thread.
   void InitWhileIOAllowed();
@@ -55,8 +58,6 @@ class ShellBrowserContext : public BrowserContext {
   scoped_refptr<GeolocationPermissionContext> geolocation_permission_context_;
   scoped_refptr<SpeechRecognitionPreferences> speech_recognition_preferences_;
 
-  ShellBrowserMainParts* shell_main_parts_;
-
   DISALLOW_COPY_AND_ASSIGN(ShellBrowserContext);
 };