Introduce browser side FrameTreeNodeBlameContext

content/browser/frame_host/frame_tree_node.h

Index: content/browser/frame_host/frame_tree_node.h
diff --git a/content/browser/frame_host/frame_tree_node.h b/content/browser/frame_host/frame_tree_node.h
index d38185808db2c6eb11f4130ed031e24a5b72a7c2..508a0a20bd51084ff593ee60a1bdb0a79f55b9a9 100644
--- a/content/browser/frame_host/frame_tree_node.h
+++ b/content/browser/frame_host/frame_tree_node.h
@@ -13,6 +13,7 @@
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "content/browser/frame_host/frame_tree_node_blame_context.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/browser/frame_host/render_frame_host_manager.h"
 #include "content/common/content_export.h"
@@ -265,13 +266,15 @@ class CONTENT_EXPORT FrameTreeNode {
   // FrameTreeNode.
   void BeforeUnloadCanceled();
 
+  FrameTreeNodeBlameContext* blame_context() const { return blame_context_; }

[Charlie Reis, 2016/04/20 16:58:58]

These all need comments, because it's not obvious what "blame context" means in
relation to the core FrameTreeNode logic.

[Xiaocheng, 2016/04/21 08:01:32]

Done.

+
+  void InitializeBlameContext();
+
  private:
   class OpenerDestroyedObserver;
 
   void set_parent(FrameTreeNode* parent) { parent_ = parent; }
 
-  void TraceSnapshot() const;
-
   // The next available browser-global FrameTreeNode ID.
   static int next_frame_tree_node_id_;
 
@@ -347,6 +350,8 @@ class CONTENT_EXPORT FrameTreeNode {
 
   base::TimeTicks last_focus_time_;
 
+  FrameTreeNodeBlameContext* blame_context_; // Not owned.
+
   DISALLOW_COPY_AND_ASSIGN(FrameTreeNode);
 };