content/shell/browser/shell.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/shell/browser/shell.h"

#include <stddef.h>

#include <map>
#include <memory>
#include <string>
#include <utility>

#include "base/callback_helpers.h"
#include "base/command_line.h"
#include "base/location.h"
#include "base/macros.h"
#include "base/no_destructor.h"
#include "base/run_loop.h"
#include "base/single_thread_task_runner.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/thread_task_runner_handle.h"
#include "build/build_config.h"
#include "content/public/browser/devtools_agent_host.h"
#include "content/public/browser/navigation_controller.h"
#include "content/public/browser/navigation_entry.h"
#include "content/public/browser/picture_in_picture_window_controller.h"
#include "content/public/browser/presentation_receiver_flags.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/render_widget_host.h"
#include "content/public/browser/renderer_preferences_util.h"
#include "content/public/browser/web_contents.h"
#include "content/public/common/content_switches.h"
#include "content/shell/app/resource.h"
#include "content/shell/browser/shell_content_browser_client.h"
#include "content/shell/browser/shell_devtools_frontend.h"
#include "content/shell/browser/shell_javascript_dialog_manager.h"
#include "content/shell/common/shell_switches.h"
#include "media/media_buildflags.h"
#include "third_party/blink/public/common/peerconnection/webrtc_ip_handling_policy.h"
#include "third_party/blink/public/common/renderer_preferences/renderer_preferences.h"

namespace content {

// Null until/unless the default main message loop is running.
base::NoDestructor<base::OnceClosure> g_quit_main_message_loop;

const int kDefaultTestWindowWidthDip = 800;
const int kDefaultTestWindowHeightDip = 600;

std::vector<Shell*> Shell::windows_;
base::OnceCallback<void(Shell*)> Shell::shell_created_callback_;

ShellPlatformDelegate* g_platform;

class Shell::DevToolsWebContentsObserver : public WebContentsObserver {
 public:
  DevToolsWebContentsObserver(Shell* shell, WebContents* web_contents)
      : WebContentsObserver(web_contents),
        shell_(shell) {
  }

  // WebContentsObserver
  void WebContentsDestroyed() override {
    shell_->OnDevToolsWebContentsDestroyed();
  }

 private:
  Shell* shell_;

  DISALLOW_COPY_AND_ASSIGN(DevToolsWebContentsObserver);
};

Shell::Shell(std::unique_ptr<WebContents> web_contents,
             bool should_set_delegate)
    : WebContentsObserver(web_contents.get()),
      web_contents_(std::move(web_contents)) {
  if (should_set_delegate)
    web_contents_->SetDelegate(this);

  if (!switches::IsRunWebTestsSwitchPresent()) {
    UpdateFontRendererPreferencesFromSystemSettings(
        web_contents_->GetMutableRendererPrefs());
  }

  windows_.push_back(this);

  if (shell_created_callback_)
    std::move(shell_created_callback_).Run(this);
}

Shell::~Shell() {
  g_platform->CleanUp(this);

  for (size_t i = 0; i < windows_.size(); ++i) {
    if (windows_[i] == this) {
      windows_.erase(windows_.begin() + i);
      break;
    }
  }

  // Always destroy WebContents before destroying ShellPlatformDelegate.
  // WebContents destruction sequence may depend on the resources destroyed with
  // ShellPlatformDelegate (e.g. the display::Screen singleton).
  web_contents_->SetDelegate(nullptr);
  web_contents_.reset();

  if (windows_.empty()) {
    delete g_platform;
    g_platform = nullptr;

    for (auto it = RenderProcessHost::AllHostsIterator(); !it.IsAtEnd();
         it.Advance()) {
      it.GetCurrentValue()->DisableKeepAliveRefCount();
    }
    if (*g_quit_main_message_loop)
      std::move(*g_quit_main_message_loop).Run();
  }
}

Shell* Shell::CreateShell(std::unique_ptr<WebContents> web_contents,
                          const gfx::Size& initial_size,
                          bool should_set_delegate) {
  WebContents* raw_web_contents = web_contents.get();
  Shell* shell = new Shell(std::move(web_contents), should_set_delegate);
  g_platform->CreatePlatformWindow(shell, initial_size);

  // Note: Do not make RenderFrameHost or RenderViewHost specific state changes
  // here, because they will be forgotten after a cross-process navigation. Use
  // RenderFrameCreated or RenderViewCreated instead.
  if (switches::IsRunWebTestsSwitchPresent()) {
    raw_web_contents->GetMutableRendererPrefs()->use_custom_colors = false;
    raw_web_contents->SyncRendererPrefs();
  }

  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
  if (command_line->HasSwitch(switches::kForceWebRtcIPHandlingPolicy)) {
    raw_web_contents->GetMutableRendererPrefs()->webrtc_ip_handling_policy =
        command_line->GetSwitchValueASCII(
            switches::kForceWebRtcIPHandlingPolicy);
  }

  g_platform->SetContents(shell);
  g_platform->DidCreateOrAttachWebContents(shell, raw_web_contents);
  // If the RenderFrame was created during WebContents construction (as happens
  // for windows opened from the renderer) then the Shell won't hear about the
  // main frame being created as a WebContentsObservers. This gives the delegate
  // a chance to act on the main frame accordingly.
  if (raw_web_contents->GetMainFrame()->IsRenderFrameCreated())
    g_platform->MainFrameCreated(shell);

  return shell;
}

void Shell::CloseAllWindows() {
  DevToolsAgentHost::DetachAllClients();

  std::vector<Shell*> open_windows(windows_);
  for (Shell* open_window : open_windows)
    open_window->Close();
  DCHECK(windows_.empty());

  // Pump the message loop to allow window teardown tasks to run.
  base::RunLoop().RunUntilIdle();
}

void Shell::SetMainMessageLoopQuitClosure(base::OnceClosure quit_closure) {
  *g_quit_main_message_loop = std::move(quit_closure);
}

void Shell::QuitMainMessageLoopForTesting() {
  if (*g_quit_main_message_loop)
    std::move(*g_quit_main_message_loop).Run();
}

void Shell::SetShellCreatedCallback(
    base::OnceCallback<void(Shell*)> shell_created_callback) {
  DCHECK(!shell_created_callback_);
  shell_created_callback_ = std::move(shell_created_callback);
}

// static
bool Shell::ShouldHideToolbar() {
  return base::CommandLine::ForCurrentProcess()->HasSwitch(
      switches::kContentShellHideToolbar);
}

Shell* Shell::FromWebContents(WebContents* web_contents) {
  for (Shell* window : windows_) {
    if (window->web_contents() && window->web_contents() == web_contents) {
      return window;
    }
  }
  return nullptr;
}

void Shell::Initialize(std::unique_ptr<ShellPlatformDelegate> platform) {
  g_platform = platform.release();
  g_platform->Initialize(GetShellDefaultSize());
}

gfx::Size Shell::AdjustWindowSize(const gfx::Size& initial_size) {
  if (!initial_size.IsEmpty())
    return initial_size;
  return GetShellDefaultSize();
}

Shell* Shell::CreateNewWindow(BrowserContext* browser_context,
                              const GURL& url,
                              const scoped_refptr<SiteInstance>& site_instance,
                              const gfx::Size& initial_size) {
  WebContents::CreateParams create_params(browser_context, site_instance);
  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kForcePresentationReceiverForTesting)) {
    create_params.starting_sandbox_flags =
        content::kPresentationReceiverSandboxFlags;
  }
  std::unique_ptr<WebContents> web_contents =
      WebContents::Create(create_params);
  Shell* shell =
      CreateShell(std::move(web_contents), AdjustWindowSize(initial_size),
                  true /* should_set_delegate */);

  if (!url.is_empty())
    shell->LoadURL(url);
  return shell;
}

void Shell::RenderFrameCreated(RenderFrameHost* frame_host) {
  if (frame_host == web_contents_->GetMainFrame())
    g_platform->MainFrameCreated(this);
}

void Shell::LoadURL(const GURL& url) {
  LoadURLForFrame(
      url, std::string(),
      ui::PageTransitionFromInt(ui::PAGE_TRANSITION_TYPED |
                                ui::PAGE_TRANSITION_FROM_ADDRESS_BAR));
}

void Shell::LoadURLForFrame(const GURL& url,
                            const std::string& frame_name,
                            ui::PageTransition transition_type) {
  NavigationController::LoadURLParams params(url);
  params.frame_name = frame_name;
  params.transition_type = transition_type;
  web_contents_->GetController().LoadURLWithParams(params);
}

void Shell::LoadDataWithBaseURL(const GURL& url, const std::string& data,
    const GURL& base_url) {
  bool load_as_string = false;
  LoadDataWithBaseURLInternal(url, data, base_url, load_as_string);
}

#if defined(OS_ANDROID)
void Shell::LoadDataAsStringWithBaseURL(const GURL& url,
                                        const std::string& data,
                                        const GURL& base_url) {
  bool load_as_string = true;
  LoadDataWithBaseURLInternal(url, data, base_url, load_as_string);
}
#endif

void Shell::LoadDataWithBaseURLInternal(const GURL& url,
                                        const std::string& data,
                                        const GURL& base_url,
                                        bool load_as_string) {
#if !defined(OS_ANDROID)
  DCHECK(!load_as_string);  // Only supported on Android.
#endif

  NavigationController::LoadURLParams params(GURL::EmptyGURL());
  const std::string data_url_header = "data:text/html;charset=utf-8,";
  if (load_as_string) {
    params.url = GURL(data_url_header);
    std::string data_url_as_string = data_url_header + data;
#if defined(OS_ANDROID)
    params.data_url_as_string =
        base::RefCountedString::TakeString(&data_url_as_string);
#endif
  } else {
    params.url = GURL(data_url_header + data);
  }

  params.load_type = NavigationController::LOAD_TYPE_DATA;
  params.base_url_for_data_url = base_url;
  params.virtual_url_for_data_url = url;
  params.override_user_agent = NavigationController::UA_OVERRIDE_FALSE;
  web_contents_->GetController().LoadURLWithParams(params);
}

void Shell::AddNewContents(WebContents* source,
                           std::unique_ptr<WebContents> new_contents,
                           const GURL& target_url,
                           WindowOpenDisposition disposition,
                           const gfx::Rect& initial_rect,
                           bool user_gesture,
                           bool* was_blocked) {
  CreateShell(
      std::move(new_contents), AdjustWindowSize(initial_rect.size()),
      !delay_popup_contents_delegate_for_testing_ /* should_set_delegate */);
}

void Shell::GoBackOrForward(int offset) {
  web_contents_->GetController().GoToOffset(offset);
}

void Shell::Reload() {
  web_contents_->GetController().Reload(ReloadType::NORMAL, false);
}

void Shell::ReloadBypassingCache() {
  web_contents_->GetController().Reload(ReloadType::BYPASSING_CACHE, false);
}

void Shell::Stop() {
  web_contents_->Stop();
}

void Shell::UpdateNavigationControls(bool to_different_document) {
  int current_index = web_contents_->GetController().GetCurrentEntryIndex();
  int max_index = web_contents_->GetController().GetEntryCount() - 1;

  g_platform->EnableUIControl(this, ShellPlatformDelegate::BACK_BUTTON,
                              current_index > 0);
  g_platform->EnableUIControl(this, ShellPlatformDelegate::FORWARD_BUTTON,
                              current_index < max_index);
  g_platform->EnableUIControl(
      this, ShellPlatformDelegate::STOP_BUTTON,
      to_different_document && web_contents_->IsLoading());
}

void Shell::ShowDevTools() {
  if (!devtools_frontend_) {
    devtools_frontend_ = ShellDevToolsFrontend::Show(web_contents());
    devtools_observer_ = std::make_unique<DevToolsWebContentsObserver>(
        this, devtools_frontend_->frontend_shell()->web_contents());
  }

  devtools_frontend_->Activate();
}

void Shell::CloseDevTools() {
  if (!devtools_frontend_)
    return;
  devtools_observer_.reset();
  devtools_frontend_->Close();
  devtools_frontend_ = nullptr;
}

void Shell::ResizeWebContentForTests(const gfx::Size& content_size) {
  g_platform->ResizeWebContent(this, content_size);
}

gfx::NativeView Shell::GetContentView() {
  if (!web_contents_)
    return nullptr;
  return web_contents_->GetNativeView();
}

#if !defined(OS_ANDROID)
gfx::NativeWindow Shell::window() {
  return g_platform->GetNativeWindow(this);
}
#endif

#if defined(OS_MAC)
void Shell::ActionPerformed(int control) {
  switch (control) {
    case IDC_NAV_BACK:
      GoBackOrForward(-1);
      break;
    case IDC_NAV_FORWARD:
      GoBackOrForward(1);
      break;
    case IDC_NAV_RELOAD:
      Reload();
      break;
    case IDC_NAV_STOP:
      Stop();
      break;
  }
}

void Shell::URLEntered(const std::string& url_string) {
  if (!url_string.empty()) {
    GURL url(url_string);
    if (!url.has_scheme())
      url = GURL("http://" + url_string);
    LoadURL(url);
  }
}
#endif

WebContents* Shell::OpenURLFromTab(WebContents* source,
                                   const OpenURLParams& params) {
  WebContents* target = nullptr;
  switch (params.disposition) {
    case WindowOpenDisposition::CURRENT_TAB:
      target = source;
      break;

    // Normally, the difference between NEW_POPUP and NEW_WINDOW is that a popup
    // should have no toolbar, no status bar, no menu bar, no scrollbars and be
    // not resizable.  For simplicity and to enable new testing scenarios in
    // content shell and web tests, popups don't get special treatment below
    // (i.e. they will have a toolbar and other things described here).
    case WindowOpenDisposition::NEW_POPUP:
    case WindowOpenDisposition::NEW_WINDOW:
    // content_shell doesn't really support tabs, but some web tests use
    // middle click (which translates into kNavigationPolicyNewBackgroundTab),
    // so we treat the cases below just like a NEW_WINDOW disposition.
    case WindowOpenDisposition::NEW_BACKGROUND_TAB:
    case WindowOpenDisposition::NEW_FOREGROUND_TAB: {
      Shell* new_window =
          Shell::CreateNewWindow(source->GetBrowserContext(),
                                 GURL(),  // Don't load anything just yet.
                                 params.source_site_instance,
                                 gfx::Size());  // Use default size.
      target = new_window->web_contents();
      break;
    }

    // No tabs in content_shell:
    case WindowOpenDisposition::SINGLETON_TAB:
    // No incognito mode in content_shell:
    case WindowOpenDisposition::OFF_THE_RECORD:
    // TODO(lukasza): Investigate if some web tests might need support for
    // SAVE_TO_DISK disposition.  This would probably require that
    // WebTestControlHost always sets up and cleans up a temporary directory
    // as the default downloads destinations for the duration of a test.
    case WindowOpenDisposition::SAVE_TO_DISK:
    // Ignoring requests with disposition == IGNORE_ACTION...
    case WindowOpenDisposition::IGNORE_ACTION:
    default:
      return nullptr;
  }

  target->GetController().LoadURLWithParams(
      NavigationController::LoadURLParams(params));
  return target;
}

void Shell::LoadingStateChanged(WebContents* source,
    bool to_different_document) {
  UpdateNavigationControls(to_different_document);
  g_platform->SetIsLoading(this, source->IsLoading());
}

#if defined(OS_ANDROID)
void Shell::SetOverlayMode(bool use_overlay_mode) {
  g_platform->SetOverlayMode(this, use_overlay_mode);
}
#endif

void Shell::EnterFullscreenModeForTab(
    RenderFrameHost* requesting_frame,
    const blink::mojom::FullscreenOptions& options) {
  ToggleFullscreenModeForTab(WebContents::FromRenderFrameHost(requesting_frame),
                             true);
}

void Shell::ExitFullscreenModeForTab(WebContents* web_contents) {
  ToggleFullscreenModeForTab(web_contents, false);
}

void Shell::ToggleFullscreenModeForTab(WebContents* web_contents,
                                       bool enter_fullscreen) {
#if defined(OS_ANDROID)
  g_platform->ToggleFullscreenModeForTab(this, web_contents, enter_fullscreen);
#endif
  if (is_fullscreen_ != enter_fullscreen) {
    is_fullscreen_ = enter_fullscreen;
    web_contents->GetMainFrame()
        ->GetRenderViewHost()
        ->GetWidget()
        ->SynchronizeVisualProperties();
  }
}

bool Shell::IsFullscreenForTabOrPending(const WebContents* web_contents) {
#if defined(OS_ANDROID)
  return g_platform->IsFullscreenForTabOrPending(this, web_contents);
#else
  return is_fullscreen_;
#endif
}

blink::mojom::DisplayMode Shell::GetDisplayMode(
    const WebContents* web_contents) {
  // TODO: should return blink::mojom::DisplayModeFullscreen wherever user puts
  // a browser window into fullscreen (not only in case of renderer-initiated
  // fullscreen mode): crbug.com/476874.
  return IsFullscreenForTabOrPending(web_contents)
             ? blink::mojom::DisplayMode::kFullscreen
             : blink::mojom::DisplayMode::kBrowser;
}

void Shell::RequestToLockMouse(WebContents* web_contents,
                               bool user_gesture,
                               bool last_unlocked_by_target) {
  // Give the platform a chance to handle the lock request, if it doesn't
  // indicate it handled it, allow the request.
  if (!g_platform->HandleRequestToLockMouse(this, web_contents, user_gesture,
                                            last_unlocked_by_target)) {
    web_contents->GotResponseToLockMouseRequest(
        blink::mojom::PointerLockResult::kSuccess);
  }
}

void Shell::Close() {
  // Shell is "self-owned" and destroys itself. The ShellPlatformDelegate
  // has the chance to co-opt this and do its own destruction.
  if (!g_platform->DestroyShell(this))
    delete this;
}

void Shell::CloseContents(WebContents* source) {
  Close();
}

bool Shell::CanOverscrollContent() {
#if defined(USE_AURA)
  return true;
#else
  return false;
#endif
}

void Shell::NavigationStateChanged(WebContents* source,
                                   InvalidateTypes changed_flags) {
  if (changed_flags & INVALIDATE_TYPE_URL)
    g_platform->SetAddressBarURL(this, source->GetVisibleURL());
}

JavaScriptDialogManager* Shell::GetJavaScriptDialogManager(
    WebContents* source) {
  if (!dialog_manager_)
    dialog_manager_ = g_platform->CreateJavaScriptDialogManager(this);
  if (!dialog_manager_)
    dialog_manager_ = std::make_unique<ShellJavaScriptDialogManager>();
  return dialog_manager_.get();
}

#if defined(OS_MAC)
void Shell::DidNavigateMainFramePostCommit(WebContents* contents) {
  g_platform->DidNavigateMainFramePostCommit(this, contents);
}

bool Shell::HandleKeyboardEvent(WebContents* source,
                                const NativeWebKeyboardEvent& event) {
  return g_platform->HandleKeyboardEvent(this, source, event);
}
#endif

bool Shell::DidAddMessageToConsole(WebContents* source,
                                   blink::mojom::ConsoleMessageLevel log_level,
                                   const std::u16string& message,
                                   int32_t line_no,
                                   const std::u16string& source_id) {
  return switches::IsRunWebTestsSwitchPresent();
}

void Shell::PortalWebContentsCreated(WebContents* portal_web_contents) {
  g_platform->DidCreateOrAttachWebContents(this, portal_web_contents);
}

void Shell::RendererUnresponsive(
    WebContents* source,
    RenderWidgetHost* render_widget_host,
    base::RepeatingClosure hang_monitor_restarter) {
  LOG(WARNING) << "renderer unresponsive";
}

void Shell::ActivateContents(WebContents* contents) {
#if !defined(OS_MAC)
  // TODO(danakj): Move this to ShellPlatformDelegate.
  contents->Focus();
#else
  // Mac headless mode is quite different than other platforms. Normally
  // focusing the WebContents would cause the OS to focus the window. Because
  // headless mac doesn't actually have system windows, we can't go down the
  // normal path and have to fake it out in the browser process.
  g_platform->ActivateContents(this, contents);
#endif
}

bool Shell::IsBackForwardCacheSupported() {
  return true;
}

std::unique_ptr<WebContents> Shell::ActivatePortalWebContents(
    WebContents* predecessor_contents,
    std::unique_ptr<WebContents> portal_contents) {
  DCHECK_EQ(predecessor_contents, web_contents_.get());
  portal_contents->SetDelegate(this);
  web_contents_->SetDelegate(nullptr);
  std::swap(web_contents_, portal_contents);
  g_platform->SetContents(this);
  g_platform->SetAddressBarURL(this, web_contents_->GetVisibleURL());
  LoadingStateChanged(web_contents_.get(), true);
  return portal_contents;
}

namespace {
class PendingCallback : public base::RefCounted<PendingCallback> {
 public:
  explicit PendingCallback(base::OnceCallback<void()> cb)
      : callback_(std::move(cb)) {}

 private:
  friend class base::RefCounted<PendingCallback>;
  ~PendingCallback() { std::move(callback_).Run(); }
  base::OnceCallback<void()> callback_;
};
}  // namespace

void Shell::UpdateInspectedWebContentsIfNecessary(
    content::WebContents* old_contents,
    content::WebContents* new_contents,
    base::OnceCallback<void()> callback) {
  scoped_refptr<PendingCallback> pending_callback =
      base::MakeRefCounted<PendingCallback>(std::move(callback));
  for (auto* shell_devtools_bindings :
       ShellDevToolsBindings::GetInstancesForWebContents(old_contents)) {
    shell_devtools_bindings->UpdateInspectedWebContents(
        new_contents,
        base::BindOnce(base::DoNothing::Once<scoped_refptr<PendingCallback>>(),
                       pending_callback));
  }
}

bool Shell::ShouldAllowRunningInsecureContent(WebContents* web_contents,
                                              bool allowed_per_prefs,
                                              const url::Origin& origin,
                                              const GURL& resource_url) {
  if (allowed_per_prefs)
    return true;

  return g_platform->ShouldAllowRunningInsecureContent(this);
}

PictureInPictureResult Shell::EnterPictureInPicture(
    WebContents* web_contents,
    const viz::SurfaceId& surface_id,
    const gfx::Size& natural_size) {
  // During tests, returning success to pretend the window was created and allow
  // tests to run accordingly.
  if (!switches::IsRunWebTestsSwitchPresent())
    return PictureInPictureResult::kNotSupported;
  return PictureInPictureResult::kSuccess;
}

bool Shell::ShouldResumeRequestsForCreatedWindow() {
  return !delay_popup_contents_delegate_for_testing_;
}

void Shell::SetContentsBounds(WebContents* source, const gfx::Rect& bounds) {
  DCHECK(source == web_contents());  // There's only one WebContents per Shell.

  if (switches::IsRunWebTestsSwitchPresent()) {
    // Note that chrome drops these requests on normal windows.
    // TODO(danakj): The position is dropped here but we use the size. Web tests
    // can't move the window in headless mode anyways, but maybe we should be
    // letting them pretend?
    g_platform->ResizeWebContent(this, bounds.size());
  }
}

gfx::Size Shell::GetShellDefaultSize() {
  static gfx::Size default_shell_size;  // Only go through this method once.

  if (!default_shell_size.IsEmpty())
    return default_shell_size;

  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
  if (command_line->HasSwitch(switches::kContentShellHostWindowSize)) {
    const std::string size_str = command_line->GetSwitchValueASCII(
                  switches::kContentShellHostWindowSize);
    int width, height;
    if (sscanf(size_str.c_str(), "%dx%d", &width, &height) == 2) {
      default_shell_size = gfx::Size(width, height);
    } else {
      LOG(ERROR) << "Invalid size \"" << size_str << "\" given to --"
                 << switches::kContentShellHostWindowSize;
    }
  }

  if (default_shell_size.IsEmpty()) {
    default_shell_size = gfx::Size(
      kDefaultTestWindowWidthDip, kDefaultTestWindowHeightDip);
  }

  return default_shell_size;
}

#if defined(OS_ANDROID)
void Shell::LoadProgressChanged(double progress) {
  g_platform->LoadProgressChanged(this, progress);
}
#endif

void Shell::TitleWasSet(NavigationEntry* entry) {
  if (entry)
    g_platform->SetTitle(this, entry->GetTitle());
}

void Shell::OnDevToolsWebContentsDestroyed() {
  devtools_observer_.reset();
  devtools_frontend_ = nullptr;
}

}  // namespace content