Track where WebContents are created in order to better understand issue.

content/browser/web_contents/web_contents_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/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
@@ skipping 2812 matching lines @@
 
   // Resume blocked requests for both the RenderViewHost and RenderFrameHost.
   // TODO(brettw): It seems bogus to reach into here and initialize the host.
   if (is_resume_pending_) {
     is_resume_pending_ = false;
     GetRenderViewHost()->Init();
     GetMainFrame()->Init();
   }
 }
 
+base::debug::StackTrace WebContentsImpl::stack_trace() {
+  return stack_trace_;
+}
+
 bool WebContentsImpl::FocusLocationBarByDefault() {
   NavigationEntry* entry = controller_.GetVisibleEntry();
   if (entry && entry->GetURL() == GURL(url::kAboutBlankURL))
     return true;
   return delegate_ && delegate_->ShouldFocusLocationBarByDefault(this);
 }
 
 void WebContentsImpl::SetFocusToLocationBar(bool select_all) {
   if (delegate_)
     delegate_->SetFocusToLocationBar(select_all);
@@ skipping 1915 matching lines @@
   return NULL;
 }
 
 void WebContentsImpl::SetForceDisableOverscrollContent(bool force_disable) {
   force_disable_overscroll_content_ = force_disable;
   if (view_)
     view_->SetOverscrollControllerEnabled(CanOverscrollContent());
 }
 
 }  // namespace content