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 51efdb457952f32d5e88c14b10c58954540d2a47..72ea38e6fddb6216ecc534a8e634a91fec8d7f12 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -283,6 +283,9 @@ 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;
@@ -598,6 +601,7 @@ class CONTENT_EXPORT WebContentsImpl
   bool FocusLocationBarByDefault() override;
   void SetFocusToLocationBar(bool select_all) override;
   bool IsHidden() override;
+  int GetOuterDelegateFrameTreeNodeID() override;
 
   // NotificationObserver ------------------------------------------------------
 
@@ -729,6 +733,28 @@ 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
+  // referred to as "inner WebContents".
+  struct WebContentsTreeNode {
+   public:
+    WebContentsTreeNode();
+    ~WebContentsTreeNode();
+
+    typedef std::set<WebContentsTreeNode*> ChildrenList;

[Charlie Reis, 2015/06/02 18:19:14]

set != list

Will we ever care about the order of the children?

[lazyboy, 2015/06/02 20:15:21]

Changed the typedef to ChildrenSet.
Don't think so. Do we want to change this to vector? The reason I made it a set
is to quickly find() and erase() in the destructor.

[Charlie Reis, 2015/06/02 23:55:43]

No, a set is fine if we don't care about the order of the children.  We can
always change it if it's needed later.

+
+    void SetOuterWebContents(WebContentsImpl* outer_web_contents);
+    WebContentsImpl* outer_web_contents() { return outer_web_contents_; }
+
+   private:
+    WebContentsImpl* outer_web_contents_;
+    ChildrenList inner_web_contents_tree_nodes_;
+  };
+
   // See WebContents::Create for a description of these parameters.
   WebContentsImpl(BrowserContext* browser_context,
                   WebContentsImpl* opener);
@@ -1045,6 +1071,10 @@ 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.
+  WebContentsTreeNode node_;

[Charlie Reis, 2015/06/02 18:19:14]

Should this be a pointer instead of inline?  The vast majority of WebContents
objects will not have one.

[lazyboy, 2015/06/02 20:15:21]

Changed to scoped_ptr.

+
   // SavePackage, lazily created.
   scoped_refptr<SavePackage> save_package_;