Implement improvements for request handling (issue #1327).

- Add a new CefRequestHandler::OnResourceResponse() method for inspecting the request/response headers and potentially restarting or redirecting the request.
- Add a new CefRequest::GetIdentifier() method for tracking a request across multiple CefRequestHandler callbacks.
- Pass a CefRequest object instead of just the old URL to CefRequestHandler::OnResourceRedirect().

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@2073 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

libcef/common/request_impl.h

@@ -48,6 +48,7 @@ class CefRequestImpl : public CefRequest {
   void SetFirstPartyForCookies(const CefString& url) override;
   ResourceType GetResourceType() override;
   TransitionType GetTransitionType() override;
+  uint64 GetIdentifier() override;
 
   // Populate this object from the URLRequest object.
   void Set(net::URLRequest* request);
@@ -77,6 +78,7 @@ class CefRequestImpl : public CefRequest {
   HeaderMap headermap_;
   ResourceType resource_type_;
   TransitionType transition_type_;
+  uint64 identifier_;
 
   // The below members are used by CefURLRequest.
   int flags_;