Introduce browser side FrameTreeNodeBlameContext

content/browser/frame_host/frame_tree_node.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/frame_host/frame_tree_node.h"
 
 #include <queue>
 #include <utility>
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/stl_util.h"
 #include "content/browser/frame_host/frame_tree.h"
 #include "content/browser/frame_host/navigation_request.h"
 #include "content/browser/frame_host/navigator.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
-#include "content/browser/frame_host/traced_frame_tree_node.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/common/frame_messages.h"
 #include "content/common/site_isolation_policy.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/browser_side_navigation_policy.h"
 #include "third_party/WebKit/public/web/WebSandboxFlags.h"
 
 namespace content {
 
 namespace {
@@ skipping 65 matching lines @@
       has_committed_real_load_(false),
       replication_state_(
           scope,
           name,
           unique_name,
           blink::WebSandboxFlags::None,
           false /* should enforce strict mixed content checking */,
           false /* is a potentially trustworthy unique origin */),
       pending_sandbox_flags_(blink::WebSandboxFlags::None),
       frame_owner_properties_(frame_owner_properties),
-      loading_progress_(kLoadingProgressNotStarted) {
+      loading_progress_(kLoadingProgressNotStarted),
+      blame_context_(nullptr) {
   std::pair<FrameTreeNodeIdMap::iterator, bool> result =
       g_frame_tree_node_id_map.Get().insert(
           std::make_pair(frame_tree_node_id_, this));
   CHECK(result.second);
-
-  TRACE_EVENT_OBJECT_CREATED_WITH_ID(
-      "navigation", "FrameTreeNode",
-      TRACE_ID_WITH_SCOPE("FrameTreeNode", frame_tree_node_id_));
-  // Don't TraceSnapshot() until the RenderFrameHostManager is initialized and
-  // calls SetCurrentURL().
 }
 
 FrameTreeNode::~FrameTreeNode() {
   children_.clear();
   frame_tree_->FrameRemoved(this);
   FOR_EACH_OBSERVER(Observer, observers_, OnFrameTreeNodeDestroyed(this));
 
   if (opener_)
     opener_->RemoveObserver(opener_observer_.get());
 
   g_frame_tree_node_id_map.Get().erase(frame_tree_node_id_);
 
-  TRACE_EVENT_OBJECT_DELETED_WITH_ID(
-      "navigation", "FrameTreeNode",
-      TRACE_ID_WITH_SCOPE("FrameTreeNode", frame_tree_node_id_));
+  // TODO(xiaochengh): Is this check necessary?
+  if (blame_context_)
+    blame_context_->ClearArguments();
 }
 
 void FrameTreeNode::AddObserver(Observer* observer) {
   observers_.AddObserver(observer);
 }
 
 void FrameTreeNode::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
 bool FrameTreeNode::IsMainFrame() const {
   return frame_tree_->root() == this;
 }
 
 FrameTreeNode* FrameTreeNode::AddChild(std::unique_ptr<FrameTreeNode> child,
                                        int process_id,
                                        int frame_routing_id) {
   // Child frame must always be created in the same process as the parent.
   CHECK_EQ(process_id, render_manager_.current_host()->GetProcess()->GetID());
   child->set_parent(this);
 
+  // TODO(xiaochengh): Is it the right timing to initialize BlameContext?
+  // It has to be after setting parent, because BlameContext::parent_id_ cannot
+  // be changed once initialized.
+  child->InitializeBlameContext();

[Xiaocheng, 2016/04/20 02:01:05]

One more question: BlameContext::parent_id_ is declared as a const, but the
topology of the frame tree can be changed -- we can, say, create a new iframe
and then put all the other existing iframes into it. Does it introduce any
issue, e.g., reassigning the parent of an existing BlameContext?

[Sami, 2016/04/20 12:15:08]

If the topology changes, the easiest thing to do is to create another blame
context with the same id as before. If this is a problem, we can modify
base::BlameContext to support changing the parent.

+
   // Initialize the RenderFrameHost for the new node.  We always create child
   // frames in the same SiteInstance as the current frame, and they can swap to
   // a different one if they navigate away.
   child->render_manager()->Init(
       render_manager_.current_host()->GetSiteInstance(),
       render_manager_.current_host()->GetRoutingID(), frame_routing_id,
       MSG_ROUTING_NONE);
 
   // Other renderer processes in this BrowsingInstance may need to find out
   // about the new frame.  Create a proxy for the child frame in all
@@ skipping 15 matching lines @@
       std::unique_ptr<FrameTreeNode> node_to_delete(std::move(*iter));
       children_.erase(iter);
       node_to_delete.reset();
       return;
     }
   }
 }
 
 void FrameTreeNode::ResetForNewProcess() {
   current_frame_host()->set_last_committed_url(GURL());
-  TraceSnapshot();
+
+  // TODO(xiaochengh): Is this check necessary?
+  if (blame_context_) {
+    blame_context_->UpdateArguments(this);
+    blame_context_->TakeSnapshot();
+  }
 
   // Remove child nodes from the tree, then delete them. This destruction
   // operation will notify observers.
   std::vector<std::unique_ptr<FrameTreeNode>>().swap(children_);
 }
 
 void FrameTreeNode::SetOpener(FrameTreeNode* opener) {
   if (opener_) {
     opener_->RemoveObserver(opener_observer_.get());
     opener_observer_.reset();
   }
 
   opener_ = opener;
 
   if (opener_) {
     if (!opener_observer_)
       opener_observer_ = base::WrapUnique(new OpenerDestroyedObserver(this));
     opener_->AddObserver(opener_observer_.get());
   }
 }
 
 void FrameTreeNode::SetCurrentURL(const GURL& url) {
   if (!has_committed_real_load_ && url != GURL(url::kAboutBlankURL))
     has_committed_real_load_ = true;
   current_frame_host()->set_last_committed_url(url);
-  TraceSnapshot();
+
+  // TODO(xiaochengh): Is this check necessary?
+  if (blame_context_) {
+    blame_context_->UpdateArguments(this);
+    blame_context_->TakeSnapshot();
+  }
 }
 
 void FrameTreeNode::SetCurrentOrigin(
     const url::Origin& origin,
     bool is_potentially_trustworthy_unique_origin) {
   if (!origin.IsSameOriginWith(replication_state_.origin) ||
       replication_state_.has_potentially_trustworthy_unique_origin !=
           is_potentially_trustworthy_unique_origin) {
     render_manager_.OnDidUpdateOrigin(origin,
                                       is_potentially_trustworthy_unique_origin);
@@ skipping 248 matching lines @@
     if (speculative_frame_host)
       speculative_frame_host->ResetLoadingState();
   } else {
     RenderFrameHostImpl* pending_frame_host =
         render_manager_.pending_frame_host();
     if (pending_frame_host)
       pending_frame_host->ResetLoadingState();
   }
 }
 
-void FrameTreeNode::TraceSnapshot() const {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(
-      "navigation", "FrameTreeNode",
-      TRACE_ID_WITH_SCOPE("FrameTreeNode", frame_tree_node_id_),
-      std::unique_ptr<base::trace_event::ConvertableToTraceFormat>(
-          new TracedFrameTreeNode(*this)));
+void FrameTreeNode::InitializeBlameContext() {
+  DCHECK(!blame_context_);
+  blame_context_ = new FrameTreeNodeBlameContext(this);

[benjhayden, 2016/04/20 01:37:34]

Where is this object deleted?

[Xiaocheng, 2016/04/20 02:01:05]

See the reply for the last comment.

+  blame_context_->Initialize();
 }
 
 }  // namespace content