Fix issues related to request and context object lifespan (issue #1037, issue #1044).

- Simplify and document the relationship between the various context object types. See browser_context.h for a description of the new relationships.
- cefclient: Add `request-context-per-browser` command-line flag for testing multiple CefRequestContext instances.
- cefclient: Add a CefURLRequest example.

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@2032 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

tests/cefclient/browser/root_window_manager.h

@@ -64,11 +64,14 @@ class RootWindowManager : public RootWindow::Delegate {
   void OnRootWindowCreated(scoped_refptr<RootWindow> root_window);
 
   // RootWindow::Delegate methods.
+  CefRefPtr<CefRequestContext> GetRequestContext(
+      RootWindow* root_window) OVERRIDE;
   void OnTest(RootWindow* root_window, int test_id) OVERRIDE;
   void OnExit(RootWindow* root_window) OVERRIDE;
   void OnRootWindowDestroyed(RootWindow* root_window) OVERRIDE;
 
   const bool terminate_when_all_windows_closed_;
+  bool request_context_per_browser_;
 
   // Existing root windows. Only accessed on the main thread.
   typedef std::set<scoped_refptr<RootWindow> > RootWindowSet;