Public Sessions - prompt the user for tabCapture requests

chrome/browser/media/webrtc/public_session_tab_capture_access_handler.cc

Index: chrome/browser/media/webrtc/public_session_tab_capture_access_handler.cc
diff --git a/chrome/browser/media/webrtc/public_session_tab_capture_access_handler.cc b/chrome/browser/media/webrtc/public_session_tab_capture_access_handler.cc
new file mode 100644
index 0000000000000000000000000000000000000000..65e2d33159f6fae40a6111a5502a2bd4e5671386
--- /dev/null
+++ b/chrome/browser/media/webrtc/public_session_tab_capture_access_handler.cc
@@ -0,0 +1,143 @@
+// 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 "chrome/browser/media/webrtc/public_session_tab_capture_access_handler.h"
+
+#include <utility>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/memory/ptr_util.h"
+#include "chromeos/login/login_state.h"
+#include "content/public/browser/web_contents.h"
+#include "extensions/common/extension.h"
+#include "extensions/common/permissions/manifest_permission_set.h"
+#include "extensions/common/permissions/permission_set.h"
+#include "extensions/common/url_pattern_set.h"
+
+namespace {
+
+// Returns true if we're in a Public Session.
+bool IsPublicSession() {
+  return chromeos::LoginState::IsInitialized() &&
+         chromeos::LoginState::Get()->IsPublicSessionUser();
+}
+
+}  // namespace
+
+PublicSessionTabCaptureAccessHandler::PublicSessionTabCaptureAccessHandler() {}
+
+PublicSessionTabCaptureAccessHandler::~PublicSessionTabCaptureAccessHandler() {}
+
+bool PublicSessionTabCaptureAccessHandler::SupportsStreamType(
+    const content::MediaStreamType type,
+    const extensions::Extension* extension) {
+  return tab_capture_access_handler_.SupportsStreamType(type, extension);
+}
+
+bool PublicSessionTabCaptureAccessHandler::CheckMediaAccessPermission(
+    content::WebContents* web_contents,
+    const GURL& security_origin,
+    content::MediaStreamType type,
+    const extensions::Extension* extension) {
+  return tab_capture_access_handler_.CheckMediaAccessPermission(
+      web_contents, security_origin, type, extension);
+}
+
+void PublicSessionTabCaptureAccessHandler::HandleRequest(
+    content::WebContents* web_contents,
+    const content::MediaStreamRequest& request,
+    const content::MediaResponseCallback& callback,
+    const extensions::Extension* extension) {
+  // This class handles requests for Public Sessions only, outside of them just
+  // pass the request through to the original class.
+  if (!IsPublicSession() || !extension) {
+    return tab_capture_access_handler_.HandleRequest(web_contents, request,
+                                                     callback, extension);
+  }
+
+  UserChoice& user_choice = user_choice_cache_[extension->id()];
+
+  if ((request.audio_type != content::MEDIA_TAB_AUDIO_CAPTURE &&
+       request.video_type != content::MEDIA_TAB_VIDEO_CAPTURE) ||
+      !user_choice.NeedsPrompting()) {
+    return ChainHandleRequest(web_contents, request, callback, extension);
+  }
+
+  user_choice.SetPrompted();
+
+  extensions::APIPermissionSet new_apis;
+  new_apis.insert(extensions::APIPermission::kTabCapture);
+  auto permission_set = base::MakeUnique<extensions::PermissionSet>(
+      new_apis, extensions::ManifestPermissionSet(),
+      extensions::URLPatternSet(), extensions::URLPatternSet());
+  auto prompt = base::MakeUnique<ExtensionInstallPrompt>(web_contents);
+
+  prompt->ShowDialog(
+      base::Bind(&PublicSessionTabCaptureAccessHandler::ResolvePermissionPrompt,
+                 base::Unretained(this), web_contents, request, callback,
+                 extension),
+      extension,
+      nullptr,  // Uses the extension icon.
+      base::MakeUnique<ExtensionInstallPrompt::Prompt>(
+          ExtensionInstallPrompt::PERMISSIONS_PROMPT),
+      std::move(permission_set),
+      ExtensionInstallPrompt::GetDefaultShowDialogCallback());
+
+  extension_install_prompt_map_[extension->id()] = std::move(prompt);
+}
+
+void PublicSessionTabCaptureAccessHandler::ChainHandleRequest(
+    content::WebContents* web_contents,
+    const content::MediaStreamRequest& request,
+    const content::MediaResponseCallback& callback,
+    const extensions::Extension* extension) {
+  DCHECK(IsPublicSession() && extension);
+  const UserChoice& user_choice = user_choice_cache_[extension->id()];
+  content::MediaStreamRequest request_copy(request);
+
+  // If the user denied tab capture, here the request gets filtered out before
+  // being passed on to the actual implementation.
+  if (!user_choice.IsAllowed()) {
+    request_copy.audio_type = content::MEDIA_NO_SERVICE;
+    request_copy.video_type = content::MEDIA_NO_SERVICE;
+  }
+
+  // Pass the request through to the original class.
+  tab_capture_access_handler_.HandleRequest(web_contents, request_copy,
+                                            callback, extension);
+}
+
+void PublicSessionTabCaptureAccessHandler::ResolvePermissionPrompt(
+    content::WebContents* web_contents,
+    const content::MediaStreamRequest& request,
+    const content::MediaResponseCallback& callback,
+    const extensions::Extension* extension,
+    ExtensionInstallPrompt::Result prompt_result) {
+  // Dispose of the prompt as it's not needed anymore.
+  extension_install_prompt_map_.erase(extension->id());
+
+  bool allowed = prompt_result == ExtensionInstallPrompt::Result::ACCEPTED;
+  UserChoice& user_choice = user_choice_cache_[extension->id()];
+
+  user_choice.Set(allowed);
+
+  ChainHandleRequest(web_contents, request, callback, extension);
+}
+
+bool PublicSessionTabCaptureAccessHandler::UserChoice::IsAllowed() const {
+  return tab_capture_allowed_;
+}
+
+bool PublicSessionTabCaptureAccessHandler::UserChoice::NeedsPrompting() const {
+  return !tab_capture_prompted_;
+}
+
+void PublicSessionTabCaptureAccessHandler::UserChoice::Set(bool allowed) {
+  tab_capture_allowed_ = allowed;
+}
+
+void PublicSessionTabCaptureAccessHandler::UserChoice::SetPrompted() {
+  tab_capture_prompted_ = true;
+}