Create FrameNavigationEntries for the initial blank page in subframes.

content/browser/frame_host/frame_tree_node.cc

Index: content/browser/frame_host/frame_tree_node.cc
diff --git a/content/browser/frame_host/frame_tree_node.cc b/content/browser/frame_host/frame_tree_node.cc
index de2cbb110482186419942d067e5cb1da726ff72a..ff775f9a16b8225b5806af09e0e601fe2d862c41 100644
--- a/content/browser/frame_host/frame_tree_node.cc
+++ b/content/browser/frame_host/frame_tree_node.cc
@@ -86,6 +86,7 @@ FrameTreeNode::FrameTreeNode(FrameTree* frame_tree,
       parent_(NULL),
       opener_(nullptr),
       opener_observer_(nullptr),
+      has_committed_real_load_(false),
       replication_state_(scope, name, sandbox_flags),
       // Effective sandbox flags also need to be set, since initial sandbox
       // flags should apply to the initial empty document in the frame.
@@ -187,6 +188,12 @@ void FrameTreeNode::SetOpener(FrameTreeNode* opener) {
   }
 }
 
+void FrameTreeNode::SetCurrentURL(const GURL& url) {
+  if (!has_committed_real_load_ && url != GURL(url::kAboutBlankURL))
+    has_committed_real_load_ = true;
+  current_url_ = url;
+}
+
 void FrameTreeNode::SetCurrentOrigin(
     const url::DeprecatedSerializedOrigin& origin) {
   if (!origin.IsSameAs(replication_state_.origin))