Create a new RenderFrameHost per child frame when --site-per-process is enabled.

content/browser/renderer_host/frame_tree_node.h

Index: content/browser/renderer_host/frame_tree_node.h
diff --git a/content/browser/web_contents/frame_tree_node.h b/content/browser/renderer_host/frame_tree_node.h
similarity index 51%
rename from content/browser/web_contents/frame_tree_node.h
rename to content/browser/renderer_host/frame_tree_node.h
index 76d2194d5c4f09116286306a656f04b2fc2a9b7a..7759741ddc2243beca141cee6d9b9420860aa646 100644
--- a/content/browser/web_contents/frame_tree_node.h
+++ b/content/browser/renderer_host/frame_tree_node.h
@@ -8,25 +8,45 @@
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "content/common/content_export.h"
 #include "url/gurl.h"
 
 namespace content {
 
+class RenderFrameHostImpl;
+
 // Any page that contains iframes has a tree structure of the frames in the
 // renderer process. We are mirroring this tree in the browser process. This
 // class represents a node in this tree and is a wrapper for all objects that
 // are frame-specific (as opposed to page-specific).
 class CONTENT_EXPORT FrameTreeNode {
  public:
-  FrameTreeNode(int64 frame_id, const std::string& name);
+  static const int64 kInvalidFrameId = -1;
+
+  FrameTreeNode(int64 frame_id, const std::string& name,
+                scoped_ptr<RenderFrameHostImpl> render_frame_host);
   ~FrameTreeNode();
 
-  // This method takes ownership of the child pointer.
-  void AddChild(FrameTreeNode* child);
+  void AddChild(scoped_ptr<FrameTreeNode> child);
   void RemoveChild(int64 child_id);
 
+  // Transitional API allowing the RenderFrameHost of a FrameTreeNode
+  // representing the main frame to be provided by someone else. After
+  // this is called, the FrameTreeNode no longer owns its RenderFrameHost.
+  //
+  // This should only be used for the main frame (aka root) in a frame tree.
+  //
+  // TODO(ajwong): Remove this method once the main frame RenderFrameHostImpl is
+  // no longer owned by the RenderViewHostImpl.
+  void ResetForMainFrame(RenderFrameHostImpl* new_render_frame_host);
+
+  void set_frame_id(int64 frame_id) {
+    DCHECK_EQ(frame_id_, kInvalidFrameId);
+    frame_id_ = frame_id;
+  }
+
   int64 frame_id() const {
     return frame_id_;
   }
@@ -51,6 +71,10 @@ class CONTENT_EXPORT FrameTreeNode {
     current_url_ = url;
   }
 
+  RenderFrameHostImpl* render_frame_host() const {
+    return render_frame_host_;
+  }
+
  private:
   // The unique identifier for the frame in the page.
   int64 frame_id_;
@@ -62,6 +86,22 @@ class CONTENT_EXPORT FrameTreeNode {
   // The immediate children of this specific frame.
   ScopedVector<FrameTreeNode> children_;
 
+  // When ResetForMainFrame() is called, this is set to false and the
+  // |render_frame_host_| below is not deleted on destruction.
+  //
+  // For the mainframe, the FrameTree does not own the |render_frame_host_|.
+  // This is a transitional wart because RenderViewHostManager does not yet
+  // have the bookeeping logic to handle creating a pending RenderFrameHost
+  // along with a pending RenderViewHost. Thus, for the main frame, the
+  // RenderViewHost currently retains ownership and the FrameTreeNode should
+  // not delete on destruction.
+  bool owns_render_frame_host_;
+
+  // The active RenderFrameHost for this frame. The FrameTreeNode does not
+  // always own this pointer.  See comments above |owns_render_frame_host_|.
+  // TODO(ajwong): Replace with RenderFrameHostManager.
+  RenderFrameHostImpl* render_frame_host_;
+
   // Track the current frame's last committed URL, so we can estimate the
   // process impact of out-of-process iframes.
   // TODO(creis): Remove this when we can store subframe URLs in the