refactor to Introduce AUDIO_CAPTURE and VIDEO_CAPTURE permissions.

chrome/browser/media/media_stream_device_permission_context.cc

Index: chrome/browser/media/media_stream_device_permission_context.cc
diff --git a/chrome/browser/media/media_stream_device_permission_context.cc b/chrome/browser/media/media_stream_device_permission_context.cc
new file mode 100644
index 0000000000000000000000000000000000000000..431a3caaff5dd9733cf25f0e11b867ee44c5cf5f
--- /dev/null
+++ b/chrome/browser/media/media_stream_device_permission_context.cc
@@ -0,0 +1,82 @@
+// 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/media_stream_device_permission_context.h"
+#include "chrome/browser/media/media_stream_device_permissions.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/common/pref_names.h"
+#include "components/content_settings/core/browser/host_content_settings_map.h"
+#include "components/content_settings/core/common/content_settings.h"
+
+MediaStreamDevicePermissionContext::MediaStreamDevicePermissionContext(
+    Profile* profile,
+    const ContentSettingsType content_settings_type)
+    : PermissionContextBase(profile, content_settings_type),
+      content_settings_type_(content_settings_type) {
+  DCHECK(content_settings_type_ == CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC ||
+         content_settings_type_ == CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA);
+}
+
+MediaStreamDevicePermissionContext::~MediaStreamDevicePermissionContext() {}
+
+void MediaStreamDevicePermissionContext::RequestPermission(
+    content::WebContents* web_contents,
+    const PermissionRequestID& id,
+    const GURL& requesting_frame,
+    bool user_gesture,
+    const BrowserPermissionCallback& callback) {
+  NOTREACHED() << "RequestPermission is not implemented";
+  callback.Run(CONTENT_SETTING_BLOCK);
+}
+
+ContentSetting MediaStreamDevicePermissionContext::GetPermissionStatus(
+    const GURL& requesting_origin,
+    const GURL& embedding_origin) const {
+  // TODO(raymes): Merge this policy check into content settings
+  // crbug.com/244389.
+  const char* policy_name = nullptr;
+  const char* urls_policy_name = nullptr;
+  if (content_settings_type_ == CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC) {

[palmer, 2015/09/01 18:31:04]

I wonder if this would be more clear/obvious as a switch case? I usually prefer
that with enums.

const char* policy_name = nullptr;
const char* urls_policy_name = nullptr;
switch (content_settings_type_) {
  case CONTENT_SETTINGS_TYPE_MEDIASTREAM_MIC:
    policy_name = prefs::kAudioCaptureAllowed;
    urls_policy_name = prefs::kAudioCaptureAllowedUrls;
    break;
  case CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA:
    // ...
    break;
  default:
    NOTREACHED();
}

[guoweis_left_chromium, 2015/09/01 19:36:33]

This class could only be used with MEDIASTREAM_MIC and MEDIASTREAM_CAMERA
(checked in ctor). Any other values don't make sense here.

+    policy_name = prefs::kAudioCaptureAllowed;
+    urls_policy_name = prefs::kAudioCaptureAllowedUrls;
+  } else {
+    DCHECK(content_settings_type_ == CONTENT_SETTINGS_TYPE_MEDIASTREAM_CAMERA);
+    policy_name = prefs::kVideoCaptureAllowed;
+    urls_policy_name = prefs::kVideoCaptureAllowedUrls;
+  }
+
+  MediaStreamDevicePolicy policy = GetDevicePolicy(
+      profile(), requesting_origin, policy_name, urls_policy_name);
+
+  if (policy == ALWAYS_DENY)

[palmer, 2015/09/01 18:31:04]

Same here, switching over the enum seems better.

[guoweis_left_chromium, 2015/09/01 19:36:33]

Done.

+    return CONTENT_SETTING_BLOCK;
+
+  if (policy == ALWAYS_ALLOW)
+    return CONTENT_SETTING_ALLOW;
+
+  DCHECK_EQ(POLICY_NOT_SET, policy);
+  // Check the content setting.
+  ContentSetting setting = PermissionContextBase::GetPermissionStatus(
+      requesting_origin, embedding_origin);
+
+  return setting == CONTENT_SETTING_DEFAULT ? CONTENT_SETTING_ASK : setting;
+}
+
+void MediaStreamDevicePermissionContext::ResetPermission(
+    const GURL& requesting_origin,
+    const GURL& embedding_origin) {
+  NOTREACHED() << "ResetPermission is not implemented";
+}
+
+void MediaStreamDevicePermissionContext::CancelPermissionRequest(
+    content::WebContents* web_contents,
+    const PermissionRequestID& id) {
+  NOTREACHED() << "CancelPermissionRequest is not implemented";
+}
+
+bool MediaStreamDevicePermissionContext::IsRestrictedToSecureOrigins() const {
+  // Flash currently doesn't require secure origin to use mic/camera. If we
+  // return true here, it'll break the use case like http://tinychat.com.
+  return false;
+}