Refactor: Make MediaCaptureDevicesDispatcher have pluggable handlers.

chrome/browser/media/desktop_capture_access_handler.cc

Index: chrome/browser/media/desktop_capture_access_handler.cc
diff --git a/chrome/browser/media/desktop_capture_access_handler.cc b/chrome/browser/media/desktop_capture_access_handler.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d240678eddaccae7ebad74e009f7868eec2e6fdc
--- /dev/null
+++ b/chrome/browser/media/desktop_capture_access_handler.cc
@@ -0,0 +1,386 @@
+// Copyright 2015 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 "chrome/browser/media/desktop_capture_access_handler.h"
+
+#include "base/command_line.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
+#include "chrome/browser/media/desktop_streams_registry.h"
+#include "chrome/browser/media/media_capture_devices_dispatcher.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_finder.h"
+#include "chrome/browser/ui/browser_window.h"
+#include "chrome/browser/ui/screen_capture_notification_ui.h"
+#include "chrome/browser/ui/simple_message_box.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/grit/generated_resources.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/desktop_media_id.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/common/media_stream_request.h"
+#include "extensions/browser/app_window/app_window.h"
+#include "extensions/browser/app_window/app_window_registry.h"
+#include "extensions/common/constants.h"
+#include "extensions/common/extension.h"
+#include "media/audio/audio_manager_base.h"
+#include "net/base/net_util.h"
+#include "third_party/webrtc/modules/desktop_capture/desktop_capture_types.h"
+#include "ui/base/l10n/l10n_util.h"
+
+#if defined(OS_CHROMEOS)
+#include "ash/shell.h"
+#include "base/sha1.h"
+#endif  // defined(OS_CHROMEOS)
+
+using content::BrowserThread;
+
+namespace {
+
+bool IsExtensionWhitelistedForScreenCapture(
+    const extensions::Extension* extension) {
+  if (!extension)
+    return false;
+
+#if defined(OS_CHROMEOS)
+  std::string hash = base::SHA1HashString(extension->id());
+  std::string hex_hash = base::HexEncode(hash.c_str(), hash.length());
+
+  // crbug.com/446688
+  return hex_hash == "4F25792AF1AA7483936DE29C07806F203C7170A0" ||
+         hex_hash == "BD8781D757D830FC2E85470A1B6E8A718B7EE0D9" ||
+         hex_hash == "4AC2B6C63C6480D150DFDA13E4A5956EB1D0DDBB" ||
+         hex_hash == "81986D4F846CEDDDB962643FA501D1780DD441BB";
+#else
+  return false;
+#endif  // defined(OS_CHROMEOS)
+}
+
+bool IsBuiltInExtension(const GURL& origin) {
+  return
+      // Feedback Extension.
+      origin.spec() == "chrome-extension://gfdkimpbcpahaombhbimeihdjnejgicl/";
+}
+
+// Helper to get title of the calling application shown in the screen capture
+// notification.
+base::string16 GetApplicationTitle(content::WebContents* web_contents,
+                                   const extensions::Extension* extension) {
+  // Use extension name as title for extensions and host/origin for drive-by
+  // web.
+  std::string title;
+  if (extension) {
+    title = extension->name();
+    return base::UTF8ToUTF16(title);
+  }
+  GURL url = web_contents->GetURL();
+  title = url.SchemeIsSecure() ? net::GetHostAndOptionalPort(url)
+                               : url.GetOrigin().spec();
+  return base::UTF8ToUTF16(title);
+}
+
+// Helper to get list of media stream devices for desktop capture in |devices|.
+// Registers to display notification if |display_notification| is true.
+// Returns an instance of MediaStreamUI to be passed to content layer.
+scoped_ptr<content::MediaStreamUI> GetDevicesForDesktopCapture(
+    content::MediaStreamDevices* devices,
+    content::DesktopMediaID media_id,
+    bool capture_audio,
+    bool display_notification,
+    const base::string16& application_title,
+    const base::string16& registered_extension_name) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  scoped_ptr<content::MediaStreamUI> ui;
+
+  // Add selected desktop source to the list.
+  devices->push_back(content::MediaStreamDevice(
+      content::MEDIA_DESKTOP_VIDEO_CAPTURE, media_id.ToString(), "Screen"));
+  if (capture_audio) {
+    // Use the special loopback device ID for system audio capture.
+    devices->push_back(content::MediaStreamDevice(
+        content::MEDIA_DESKTOP_AUDIO_CAPTURE,
+        media::AudioManagerBase::kLoopbackInputDeviceId, "System Audio"));
+  }
+
+  // If required, register to display the notification for stream capture.
+  if (display_notification) {
+    if (application_title == registered_extension_name) {
+      ui = ScreenCaptureNotificationUI::Create(l10n_util::GetStringFUTF16(
+          IDS_MEDIA_SCREEN_CAPTURE_NOTIFICATION_TEXT, application_title));
+    } else {
+      ui = ScreenCaptureNotificationUI::Create(l10n_util::GetStringFUTF16(
+          IDS_MEDIA_SCREEN_CAPTURE_NOTIFICATION_TEXT_DELEGATED,
+          registered_extension_name, application_title));
+    }
+  }
+
+  return ui.Pass();
+}
+
+#if !defined(OS_ANDROID)
+// Find browser or app window from a given |web_contents|.
+gfx::NativeWindow FindParentWindowForWebContents(
+    content::WebContents* web_contents) {
+  Browser* browser = chrome::FindBrowserWithWebContents(web_contents);
+  if (browser && browser->window())
+    return browser->window()->GetNativeWindow();
+
+  const extensions::AppWindowRegistry::AppWindowList& window_list =
+      extensions::AppWindowRegistry::Get(web_contents->GetBrowserContext())
+          ->app_windows();
+  for (extensions::AppWindowRegistry::AppWindowList::const_iterator iter =
+           window_list.begin();
+       iter != window_list.end(); ++iter) {
+    if ((*iter)->web_contents() == web_contents)
+      return (*iter)->GetNativeWindow();
+  }
+
+  return NULL;
+}
+#endif
+
+}  // namespace
+
+DesktopCaptureAccessHandler::DesktopCaptureAccessHandler() {
+}
+
+DesktopCaptureAccessHandler::~DesktopCaptureAccessHandler() {
+}
+
+void DesktopCaptureAccessHandler::ProcessScreenCaptureAccessRequest(
+    content::WebContents* web_contents,
+    const content::MediaStreamRequest& request,
+    const content::MediaResponseCallback& callback,
+    const extensions::Extension* extension) {
+  content::MediaStreamDevices devices;
+  scoped_ptr<content::MediaStreamUI> ui;
+
+  DCHECK_EQ(request.video_type, content::MEDIA_DESKTOP_VIDEO_CAPTURE);
+
+  bool loopback_audio_supported = false;
+#if defined(USE_CRAS) || defined(OS_WIN)
+  // Currently loopback audio capture is supported only on Windows and ChromeOS.
+  loopback_audio_supported = true;
+#endif
+
+  bool component_extension = false;
+  component_extension =
+      extension && extension->location() == extensions::Manifest::COMPONENT;
+
+  bool screen_capture_enabled =
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableUserMediaScreenCapturing) ||
+      MediaCaptureDevicesDispatcher::IsOriginForCasting(
+          request.security_origin) ||
+      IsExtensionWhitelistedForScreenCapture(extension) ||
+      IsBuiltInExtension(request.security_origin);
+
+  const bool origin_is_secure =
+      request.security_origin.SchemeIsSecure() ||
+      request.security_origin.SchemeIs(extensions::kExtensionScheme) ||
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kAllowHttpScreenCapture);
+
+  // If basic conditions (screen capturing is enabled and origin is secure)
+  // aren't fulfilled, we'll use "invalid state" as result. Otherwise, we set
+  // it after checking permission.
+  // TODO(grunell): It would be good to change this result for something else,
+  // probably a new one.
+  content::MediaStreamRequestResult result =
+      content::MEDIA_DEVICE_INVALID_STATE;
+
+  // Approve request only when the following conditions are met:
+  //  1. Screen capturing is enabled via command line switch or white-listed for
+  //     the given origin.
+  //  2. Request comes from a page with a secure origin or from an extension.
+  if (screen_capture_enabled && origin_is_secure) {
+    // Get title of the calling application prior to showing the message box.
+    // chrome::ShowMessageBox() starts a nested message loop which may allow
+    // |web_contents| to be destroyed on the UI thread before the message box
+    // is closed. See http://crbug.com/326690.
+    base::string16 application_title =
+        GetApplicationTitle(web_contents, extension);
+#if !defined(OS_ANDROID)
+    gfx::NativeWindow parent_window =
+        FindParentWindowForWebContents(web_contents);
+#else
+    gfx::NativeWindow parent_window = NULL;
+#endif
+    web_contents = NULL;
+
+    bool whitelisted_extension =
+        IsExtensionWhitelistedForScreenCapture(extension);
+
+    // For whitelisted or component extensions, bypass message box.
+    bool user_approved = false;
+    if (!whitelisted_extension && !component_extension) {
+      base::string16 application_name =
+          base::UTF8ToUTF16(request.security_origin.spec());
+      if (extension)
+        application_name = base::UTF8ToUTF16(extension->name());
+      base::string16 confirmation_text = l10n_util::GetStringFUTF16(
+          request.audio_type == content::MEDIA_NO_SERVICE
+              ? IDS_MEDIA_SCREEN_CAPTURE_CONFIRMATION_TEXT
+              : IDS_MEDIA_SCREEN_AND_AUDIO_CAPTURE_CONFIRMATION_TEXT,
+          application_name);
+      chrome::MessageBoxResult result = chrome::ShowMessageBox(
+          parent_window,
+          l10n_util::GetStringFUTF16(
+              IDS_MEDIA_SCREEN_CAPTURE_CONFIRMATION_TITLE, application_name),
+          confirmation_text, chrome::MESSAGE_BOX_TYPE_QUESTION);
+      user_approved = (result == chrome::MESSAGE_BOX_RESULT_YES);
+    }
+
+    if (user_approved || component_extension || whitelisted_extension) {
+      content::DesktopMediaID screen_id;
+#if defined(OS_CHROMEOS)
+      screen_id = content::DesktopMediaID::RegisterAuraWindow(
+          ash::Shell::GetInstance()->GetPrimaryRootWindow());
+#else   // defined(OS_CHROMEOS)
+      screen_id = content::DesktopMediaID(content::DesktopMediaID::TYPE_SCREEN,
+                                          webrtc::kFullDesktopScreenId);
+#endif  // !defined(OS_CHROMEOS)
+
+      bool capture_audio =
+          (request.audio_type == content::MEDIA_DESKTOP_AUDIO_CAPTURE &&
+           loopback_audio_supported);
+
+      // Unless we're being invoked from a component extension, register to
+      // display the notification for stream capture.
+      bool display_notification = !component_extension;
+
+      ui = GetDevicesForDesktopCapture(&devices, screen_id, capture_audio,
+                                       display_notification, application_title,
+                                       application_title);
+      DCHECK(!devices.empty());
+    }
+
+    // The only case when devices can be empty is if the user has denied
+    // permission.
+    result = devices.empty() ? content::MEDIA_DEVICE_PERMISSION_DENIED
+                             : content::MEDIA_DEVICE_OK;
+  }
+
+  callback.Run(devices, result, ui.Pass());
+}
+
+bool DesktopCaptureAccessHandler::SupportsStreamType(
+    const content::MediaStreamType type,
+    const extensions::Extension* extension) {
+  return type == content::MEDIA_DESKTOP_VIDEO_CAPTURE ||
+         type == content::MEDIA_DESKTOP_AUDIO_CAPTURE;
+}
+
+bool DesktopCaptureAccessHandler::CheckMediaAccessPermission(
+    content::WebContents* web_contents,
+    const GURL& security_origin,
+    content::MediaStreamType type,
+    const extensions::Extension* extension) {
+  return false;
+}
+
+void DesktopCaptureAccessHandler::HandleRequest(
+    content::WebContents* web_contents,
+    const content::MediaStreamRequest& request,
+    const content::MediaResponseCallback& callback,
+    const extensions::Extension* extension) {
+  content::MediaStreamDevices devices;
+  scoped_ptr<content::MediaStreamUI> ui;
+
+  if (request.video_type != content::MEDIA_DESKTOP_VIDEO_CAPTURE) {
+    callback.Run(devices, content::MEDIA_DEVICE_INVALID_STATE, ui.Pass());
+    return;
+  }
+
+  // If the device id wasn't specified then this is a screen capture request
+  // (i.e. chooseDesktopMedia() API wasn't used to generate device id).
+  if (request.requested_video_device_id.empty()) {
+    ProcessScreenCaptureAccessRequest(web_contents, request, callback,
+                                      extension);
+    return;
+  }
+
+  // The extension name that the stream is registered with.
+  std::string original_extension_name;
+  // Resolve DesktopMediaID for the specified device id.
+  content::DesktopMediaID media_id;
+  // TODO(miu): Replace "main RenderFrame" IDs with the request's actual
+  // RenderFrame IDs once the desktop capture extension API implementation is
+  // fixed.  http://crbug.com/304341
+  content::WebContents* const web_contents_for_stream =
+      content::WebContents::FromRenderFrameHost(
+          content::RenderFrameHost::FromID(request.render_process_id,
+                                           request.render_frame_id));
+  content::RenderFrameHost* const main_frame =
+      web_contents_for_stream ? web_contents_for_stream->GetMainFrame() : NULL;
+  if (main_frame) {
+    media_id = MediaCaptureDevicesDispatcher::GetInstance()
+                   ->GetDesktopStreamsRegistry()
+                   ->RequestMediaForStreamId(request.requested_video_device_id,
+                                             main_frame->GetProcess()->GetID(),
+                                             main_frame->GetRoutingID(),
+                                             request.security_origin,
+                                             &original_extension_name);
+  }
+
+  // Received invalid device id.
+  if (media_id.type == content::DesktopMediaID::TYPE_NONE) {
+    callback.Run(devices, content::MEDIA_DEVICE_INVALID_STATE, ui.Pass());
+    return;
+  }
+
+  bool loopback_audio_supported = false;
+#if defined(USE_CRAS) || defined(OS_WIN)
+  // Currently loopback audio capture is supported only on Windows and ChromeOS.
+  loopback_audio_supported = true;
+#endif
+
+  // Audio is only supported for screen capture streams.
+  bool capture_audio =
+      (media_id.type == content::DesktopMediaID::TYPE_SCREEN &&
+       request.audio_type == content::MEDIA_DESKTOP_AUDIO_CAPTURE &&
+       loopback_audio_supported);
+
+  ui = GetDevicesForDesktopCapture(&devices, media_id, capture_audio, true,
+                                   GetApplicationTitle(web_contents, extension),
+                                   base::UTF8ToUTF16(original_extension_name));
+
+  callback.Run(devices, content::MEDIA_DEVICE_OK, ui.Pass());
+}
+
+void DesktopCaptureAccessHandler::UpdateMediaRequestState(
+    int render_process_id,
+    int render_frame_id,
+    int page_request_id,
+    content::MediaStreamType stream_type,
+    content::MediaRequestState state) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  // Track desktop capture sessions.  Tracking is necessary to avoid unbalanced
+  // session counts since not all requests will reach MEDIA_REQUEST_STATE_DONE,
+  // but they will all reach MEDIA_REQUEST_STATE_CLOSING.
+  if (stream_type != content::MEDIA_DESKTOP_VIDEO_CAPTURE)
+    return;
+
+  if (state == content::MEDIA_REQUEST_STATE_DONE) {
+    DesktopCaptureSession session = {
+        render_process_id, render_frame_id, page_request_id};
+    desktop_capture_sessions_.push_back(session);
+  } else if (state == content::MEDIA_REQUEST_STATE_CLOSING) {
+    for (DesktopCaptureSessions::iterator it =
+             desktop_capture_sessions_.begin();
+         it != desktop_capture_sessions_.end(); ++it) {
+      if (it->render_process_id == render_process_id &&
+          it->render_frame_id == render_frame_id &&
+          it->page_request_id == page_request_id) {
+        desktop_capture_sessions_.erase(it);
+        break;
+      }
+    }
+  }
+}
+
+bool DesktopCaptureAccessHandler::IsCaptureInProgress() {
+  return desktop_capture_sessions_.size() > 0;
+}