Add some tracing to most expensive accessibility functions.

content/renderer/accessibility/render_accessibility_impl.cc

 // Copyright (c) 2012 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/renderer/accessibility/render_accessibility_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <queue>
@@ skipping 41 matching lines @@
 
 // Cap the number of nodes returned in an accessibility
 // tree snapshot to avoid outrageous memory or bandwidth
 // usage.
 const size_t kMaxSnapshotNodeCount = 5000;
 
 // static
 void RenderAccessibilityImpl::SnapshotAccessibilityTree(
     RenderFrameImpl* render_frame,
     AXContentTreeUpdate* response) {
+  TRACE_EVENT0("accessibility",
+               "RenderAccessibilityImpl::SnapshotAccessibilityTree");
+
   DCHECK(render_frame);
   DCHECK(response);
   if (!render_frame->GetWebFrame())
     return;
 
   WebDocument document = render_frame->GetWebFrame()->GetDocument();
   WebScopedAXContext context(document);
   WebAXObject root = context.Root();
   if (!root.UpdateLayoutAndCheckValidity())
     return;
@@ skipping 263 matching lines @@
   }
 }
 
 WebDocument RenderAccessibilityImpl::GetMainDocument() {
   if (render_frame_ && render_frame_->GetWebFrame())
     return render_frame_->GetWebFrame()->GetDocument();
   return WebDocument();
 }
 
 void RenderAccessibilityImpl::SendPendingAccessibilityEvents() {
+  TRACE_EVENT0("accessibility",
+               "RenderAccessibilityImpl::SendPendingAccessibilityEvents");
+
   const WebDocument& document = GetMainDocument();
   if (document.IsNull())
     return;
 
   if (pending_events_.empty())
     return;
 
   ack_pending_ = true;
 
   // Make a copy of the events, because it's possible that
@@ skipping 65 matching lines @@
 
   Send(new AccessibilityHostMsg_Events(routing_id(), event_msgs, reset_token_,
                                        ack_token_));
   reset_token_ = 0;
 
   if (had_layout_complete_messages)
     SendLocationChanges();
 }
 
 void RenderAccessibilityImpl::SendLocationChanges() {
+  TRACE_EVENT0("accessibility", "RenderAccessibilityImpl::SendLocationChanges");
+
   std::vector<AccessibilityHostMsg_LocationChangeParams> messages;
 
   // Update layout on the root of the tree.
   ScopedFreezeBlinkAXTreeSource freeze(&tree_source_);
   WebAXObject root = tree_source_.GetRoot();
   if (!root.UpdateLayoutAndCheckValidity())
     return;
 
   // Do a breadth-first explore of the whole blink AX tree.
   base::hash_map<int, ui::AXRelativeBounds> new_locations;
@@ skipping 269 matching lines @@
 
   const WebDocument& document = GetMainDocument();
   if (document.IsNull())
     return;
 
   document.AccessibilityObject().ScrollToMakeVisibleWithSubFocus(
       WebRect(bounds.x(), bounds.y(), bounds.width(), bounds.height()));
 }
 
 }  // namespace content