Make <webview> use out-of-process iframe architecture.

content/browser/web_contents/web_contents_impl.h

Index: content/browser/web_contents/web_contents_impl.h
diff --git a/content/browser/web_contents/web_contents_impl.h b/content/browser/web_contents/web_contents_impl.h
index 005b59137c8b24e68ce6b4ef353f1d8f82679304..15591aa0ec3a468e876a5202dc88a43ebaab85ab 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -279,6 +279,9 @@ class CONTENT_EXPORT WebContentsImpl
   void WasHidden() override;
   bool NeedToFireBeforeUnload() override;
   void DispatchBeforeUnload(bool for_cross_site_transition) override;
+  void AttachToOuterWebContentsFrame(
+      WebContents* outer_web_contents,
+      RenderFrameHost* outer_contents_frame) override;
   void Stop() override;
   WebContents* Clone() override;
   void ReloadFocusedFrame(bool ignore_cache) override;
@@ -594,6 +597,7 @@ class CONTENT_EXPORT WebContentsImpl
   bool FocusLocationBarByDefault() override;
   void SetFocusToLocationBar(bool select_all) override;
   bool IsHidden() override;
+  int GetOuterDelegateFrameTreeNodeID() override;
 
   // NotificationObserver ------------------------------------------------------
 
@@ -725,6 +729,34 @@ class CONTENT_EXPORT WebContentsImpl
 
   class DestructionObserver;
 
+  // Represents a WebContents node in a tree of WebContents structure.
+  //
+  // Two WebContents with separate FrameTrees can be connected by
+  // outer/inner relationship using this class. Note that their FrameTrees
+  // still remain disjoint.
+  // The root is referred to as "outer WebContents" and the descendents are

[nasko, 2015/06/15 23:00:13]

It is not just the root that will be outer WebContents, will it? Any two
WebContents's that are connected together are outer/inner, no?

[lazyboy, 2015/06/16 17:59:52]

That's right, I've changed root -> parent.

+  // referred to as "inner WebContents".
+  struct WebContentsTreeNode {
+   public:
+    WebContentsTreeNode();
+    ~WebContentsTreeNode();
+
+    typedef std::set<WebContentsTreeNode*> ChildrenSet;
+
+    void ConnectToOuterWebContents(WebContentsImpl* outer_web_contents,
+                                   RenderFrameHostImpl* outer_contents_frame);
+
+    int outer_contents_frame_tree_node_id() {
+      return outer_contents_frame_tree_node_id_;
+    }
+    WebContentsImpl* outer_web_contents() { return outer_web_contents_; }
+
+   private:
+    int outer_contents_frame_tree_node_id_;

[nasko, 2015/06/15 23:00:14]

nit: Should this be const? The outer WebContents and the FTN id won't change for
the lifetime of this connection, right?

[lazyboy, 2015/06/16 17:59:52]

You can removeChild(<webview>) and then appendChild to another local
subframe in the outer WebContents, so this shouldn't be const.

+    WebContentsImpl* outer_web_contents_;
+    ChildrenSet inner_web_contents_tree_nodes_;
+  };
+
   // See WebContents::Create for a description of these parameters.
   WebContentsImpl(BrowserContext* browser_context);
 
@@ -1036,6 +1068,10 @@ class CONTENT_EXPORT WebContentsImpl
   // Manages the frame tree of the page and process swaps in each node.
   FrameTree frame_tree_;
 
+  // If this WebContents is part of a "tree of WebContents", then this contains
+  // information about the structure.
+  scoped_ptr<WebContentsTreeNode> node_;
+
   // SavePackage, lazily created.
   scoped_refptr<SavePackage> save_package_;