Introduce base classes for blame contexts

tracing/tracing/extras/chrome/blame_context/frame_tree_node.html

Index: tracing/tracing/extras/chrome/blame_context/frame_tree_node.html
diff --git a/tracing/tracing/extras/chrome/frame_tree_node.html b/tracing/tracing/extras/chrome/blame_context/frame_tree_node.html
similarity index 47%
rename from tracing/tracing/extras/chrome/frame_tree_node.html
rename to tracing/tracing/extras/chrome/blame_context/frame_tree_node.html
index dde8fc28d1f8bc6a061fa07169cf7f27660fe872..7916e3dfe4eae1e7a8a1b098aba00607f0d8ed7b 100644
--- a/tracing/tracing/extras/chrome/frame_tree_node.html
+++ b/tracing/tracing/extras/chrome/blame_context/frame_tree_node.html
@@ -5,28 +5,35 @@ Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 
-<link rel="import" href="/tracing/model/object_instance.html">
+<link rel="import" href="/tracing/extras/chrome/blame_context/blame_context.html">
 
 <script>
 'use strict';
 
+/**
+ * @fileoverview Trace Viewer side's correspondence of Chrome's
+ * content::FrameTreeNode class.
+ *
+ */
 tr.exportTo('tr.e.chrome', function() {
-  var constants = tr.e.cc.constants;
-
-  var ObjectSnapshot = tr.model.ObjectSnapshot;
-  var ObjectInstance = tr.model.ObjectInstance;
+  var BlameContextSnapshot = tr.e.chrome.BlameContextSnapshot;
+  var BlameContextInstance = tr.e.chrome.BlameContextInstance;
 
   function FrameTreeNodeSnapshot() {
-    ObjectSnapshot.apply(this, arguments);
+    BlameContextSnapshot.apply(this, arguments);
   }
 
   FrameTreeNodeSnapshot.prototype = {
-    __proto__: ObjectSnapshot.prototype,
+    __proto__: BlameContextSnapshot.prototype,
 
-    preInitialize: function() {
+    get renderFrame() {
+      if (this.args.renderFrame instanceof tr.e.chrome.RenderFrameSnapshot)
+        return this.args.renderFrame;
+      return undefined;
     },
 
-    initialize: function() {
+    get url() {
+      return this.args.url;
     },
 
     get userFriendlyName() {
@@ -34,19 +41,23 @@ tr.exportTo('tr.e.chrome', function() {
     }
   };
 
-  ObjectSnapshot.register(
+  tr.model.ObjectSnapshot.register(
       FrameTreeNodeSnapshot,
       {typeName: 'FrameTreeNode'});
 
   function FrameTreeNodeInstance() {
-    ObjectInstance.apply(this, arguments);
+    BlameContextInstance.apply(this, arguments);
   }
 
   FrameTreeNodeInstance.prototype = {
-    __proto__: ObjectInstance.prototype
+    __proto__: BlameContextInstance.prototype,
+
+    get blameContextType() {
+      return 'Frame';
+    }
   };
 
-  ObjectInstance.register(
+  tr.model.ObjectInstance.register(
       FrameTreeNodeInstance,
       {typeName: 'FrameTreeNode'});