[WebLayer] Fix crash in weblayer_shell on desktop

permissions::PermissionManager::PermissionTypeToContentSetting DCHECKs
when called on PROTECTED_MEDIA_IDENTIFIER on desktop, since it is
Android/ChromeOS only.

Change-Id: Ie9e69ed5edda49fee03e44980acaf864d9776d2c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2134502
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Commit-Queue: Evan Stade <estade@chromium.org>
Auto-Submit: Clark DuVall <cduvall@chromium.org>
Reviewed-by: Evan Stade <estade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#756116}

weblayer/browser/permissions/permission_manager_factory.cc

@@ -66,14 +66,21 @@ permissions::PermissionManager::PermissionContextMap CreatePermissionContexts(
           browser_context,
           std::make_unique<GeolocationPermissionContextDelegate>());
 
+#if defined(OS_CHROMEOS) || defined(OS_ANDROID)
   permission_contexts[ContentSettingsType::PROTECTED_MEDIA_IDENTIFIER] =
       std::make_unique<SafePermissionContext>(
           browser_context, ContentSettingsType::PROTECTED_MEDIA_IDENTIFIER,
           blink::mojom::FeaturePolicyFeature::kEncryptedMedia);
+#endif
 
   // For now, all requests are denied. As features are added, their permission
   // contexts can be added here instead of DeniedPermissionContext.
   for (content::PermissionType type : content::GetAllPermissionTypes()) {
+#if !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
+    // PROTECTED_MEDIA_IDENTIFIER is only supported on Android/ChromeOS.
+    if (type == content::PermissionType::PROTECTED_MEDIA_IDENTIFIER)
+      continue;
+#endif
     ContentSettingsType content_settings_type =
         permissions::PermissionManager::PermissionTypeToContentSetting(type);
     if (permission_contexts.find(content_settings_type) ==