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 350d1ca02b5235e24b49fa9cf31d96bebfef7414..56c3e898d17f8d57bba0c3801d62e7ff4c9c5bd3 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -279,6 +279,8 @@ class CONTENT_EXPORT WebContentsImpl
   void WasHidden() override;
   bool NeedToFireBeforeUnload() override;
   void DispatchBeforeUnload(bool for_cross_site_transition) override;
+  void AttachToEmbedderFrame(WebContents* embedder_web_contents,
+                             RenderFrameHost* embedder_frame) override;
   void Stop() override;
   WebContents* Clone() override;
   void ReloadFocusedFrame(bool ignore_cache) override;
@@ -598,6 +600,7 @@ class CONTENT_EXPORT WebContentsImpl
   bool FocusLocationBarByDefault() override;
   void SetFocusToLocationBar(bool select_all) override;
   bool IsHidden() override;
+  int64 GetEmbedderFrameTreeNodeID() override;
 
   // NotificationObserver ------------------------------------------------------
 
@@ -733,6 +736,25 @@ class CONTENT_EXPORT WebContentsImpl
 
   class DestructionObserver;
 
+  // Represents a WebContents node in a tree of WebContents structure.
+  //
+  // Two WebContents with separate FrameTree can be connected by
+  // parent-child relationship using this class. Note that their FrameTrees
+  // still remain disjoint/separate.
+  struct WebContentsTreeNode {
+   public:
+    WebContentsTreeNode();
+    ~WebContentsTreeNode();
+
+    void set_parent_web_contents(WebContentsImpl* parent_web_contents) {
+      parent_web_contents_ = parent_web_contents;
+    }
+    WebContentsImpl* parent_web_contents() { return parent_web_contents_; }
+
+   private:
+    WebContentsImpl* parent_web_contents_;
+  };
+
   // See WebContents::Create for a description of these parameters.
   WebContentsImpl(BrowserContext* browser_context,
                   WebContentsImpl* opener);
@@ -1047,6 +1069,10 @@ 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" structure, then
+  // this contain information about the structure.
+  WebContentsTreeNode node_;
+
   // SavePackage, lazily created.
   scoped_refptr<SavePackage> save_package_;