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/osr_window_win.cc

@@ -82,12 +82,13 @@ void OsrWindowWin::CreateBrowser(HWND parent_hwnd,
                                  const RECT& rect,
                                  CefRefPtr<CefClient> handler,
                                  const CefBrowserSettings& settings,
+                                 CefRefPtr<CefRequestContext> request_context,
                                  const std::string& startup_url) {
   if (!CefCurrentlyOn(TID_UI)) {
     // Execute this method on the UI thread.
     CefPostTask(TID_UI, base::Bind(&OsrWindowWin::CreateBrowser, this,
                                    parent_hwnd, rect, handler, settings,
-                                   startup_url));
+                                   request_context, startup_url));
     return;
   }
 
@@ -99,7 +100,7 @@ void OsrWindowWin::CreateBrowser(HWND parent_hwnd,
 
   // Create the browser asynchronously.
   CefBrowserHost::CreateBrowser(window_info, handler, startup_url, settings,
-                                NULL);
+                                request_context);
 }
 
 void OsrWindowWin::ShowPopup(HWND parent_hwnd,