Add hovering feature to AshDevToolsDOMAgent

ash/common/devtools/ash_devtools_unittest.cc

 // Copyright 2016 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 "ash/common/devtools/ash_devtools_dom_agent.h"
 
 #include "ash/common/test/ash_test.h"
 #include "ash/common/wm_lookup.h"
 #include "ash/common/wm_root_window_controller.h"
 #include "ash/common/wm_shell.h"
 #include "ash/common/wm_window.h"
 #include "base/strings/stringprintf.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "ui/views/widget/native_widget_private.h"
 #include "ui/views/widget/widget.h"
 
 namespace ash {
 namespace {
 using namespace ui::devtools::protocol;
 const int kDefaultChildNodeCount = -1;
 
 class TestView : public views::View {
  public:
@@ skipping 110 matching lines @@
             widget, kShellWindowId_DefaultContainer, &params);
     widget->Init(params);
     return widget->native_widget_private();
   }
 
   void SetUp() override {
     AshTest::SetUp();
     fake_frontend_channel_ = base::MakeUnique<FakeFrontendChannel>();
     uber_dispatcher_ =
         base::MakeUnique<UberDispatcher>(fake_frontend_channel_.get());
-    dom_agent_ =
-        base::MakeUnique<devtools::AshDevToolsDOMAgent>(WmShell::Get());
+    dom_agent_ = base::MakeUnique<devtools::AshDevToolsDOMAgent>(
+        WmShell::Get(), base::ThreadTaskRunnerHandle::Get());
     dom_agent_->Init(uber_dispatcher_.get());
   }
 
   void TearDown() override {
     dom_agent_.reset();
     uber_dispatcher_.reset();
     fake_frontend_channel_.reset();
     AshTest::TearDown();
   }
 
@@ skipping 313 matching lines @@
   Compare(target_view, target_view_node);
   Compare(child_view, child_view_node);
   parent_view->RemoveChildView(child_view);
   target_view->AddChildView(child_view);
   ExpectChildNodeRemoved(parent_view_node->getNodeId(),
                          child_view_node->getNodeId());
   ExpectChildNodeInserted(target_view_node->getNodeId(), 0);
 }
 
 }  // namespace ash