Solidify Entry discarding logic (NavigationHandle keeps its ID)

content/browser/frame_host/navigation_handle_impl.h

Index: content/browser/frame_host/navigation_handle_impl.h
diff --git a/content/browser/frame_host/navigation_handle_impl.h b/content/browser/frame_host/navigation_handle_impl.h
index f5ce726575ac464eb8cfe115cfa0aa4f663afe63..fed4a749d74c780e9524372671cecd52353d8916 100644
--- a/content/browser/frame_host/navigation_handle_impl.h
+++ b/content/browser/frame_host/navigation_handle_impl.h
@@ -70,7 +70,8 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
   static scoped_ptr<NavigationHandleImpl> Create(
       const GURL& url,
       FrameTreeNode* frame_tree_node,
-      const base::TimeTicks& navigation_start);
+      const base::TimeTicks& navigation_start,
+      int pending_nav_entry_id);
   ~NavigationHandleImpl() override;
 
   // NavigationHandle implementation:
@@ -112,6 +113,11 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
   // in the network stack.
   const net::HttpResponseHeaders* GetResponseHeaders();
 
+  // Get the unique id from the NavigationEntry associated with this
+  // NavigationHandle. Note that a synchronous, renderer-initiated navigation
+  // will not have a NavigationEntry associated with it, and this will return 0.
+  int pending_nav_entry_id() const { return pending_nav_entry_id_; }
+
   void set_net_error_code(net::Error net_error_code) {
     net_error_code_ = net_error_code;
   }
@@ -215,7 +221,8 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
 
   NavigationHandleImpl(const GURL& url,
                        FrameTreeNode* frame_tree_node,
-                       const base::TimeTicks& navigation_start);
+                       const base::TimeTicks& navigation_start,
+                       int pending_nav_entry_id);
 
   NavigationThrottle::ThrottleCheckResult CheckWillStartRequest();
   NavigationThrottle::ThrottleCheckResult CheckWillRedirectRequest();
@@ -259,6 +266,9 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
   // The time this navigation started.
   const base::TimeTicks navigation_start_;
 
+  // The unique id of the corresponding NavigationEntry.
+  const int pending_nav_entry_id_;
+
   // This callback will be run when all throttle checks have been performed.
   ThrottleChecksFinishedCallback complete_callback_;