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

libcef/browser/url_request_context_impl.h

@@ -0,0 +1,22 @@
+// Copyright (c) 2015 The Chromium Embedded Framework Authors. All rights
+// reserved. Use of this source code is governed by a BSD-style license that can
+// be found in the LICENSE file.
+
+#ifndef CEF_LIBCEF_BROWSER_URL_REQUEST_CONTEXT_IMPL_H_
+#define CEF_LIBCEF_BROWSER_URL_REQUEST_CONTEXT_IMPL_H_
+#pragma once
+
+#include "libcef/browser/url_request_context.h"
+
+// Global URLRequestContext implementation. Life span is controlled by
+// CefURLRequestContextGetterImpl. Only accessed on the IO thread. See
+// browser_context.h for an object relationship diagram.
+class CefURLRequestContextImpl : public CefURLRequestContext {
+ public:
+  CefURLRequestContextImpl() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CefURLRequestContextImpl);
+};
+
+#endif  // CEF_LIBCEF_BROWSER_URL_REQUEST_CONTEXT_IMPL_H_