extensions: guest_view: provide API to update default media access permission

This provides an ability to programmatically grant media access permission
for a guest view, which is a desired feature on certain devices.

Bug: b/78193883
Test: Build
Change-Id: If733c28125e4228a1c50baf11f9715c7d876da67
Reviewed-on: https://chromium-review.googlesource.com/1021599Reviewed-by: Fady Samuel <fsamuel@chromium.org>
Commit-Queue: Peter Qiu <zqiu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552926}

extensions/browser/guest_view/web_view/web_view_permission_helper.cc

@@ -150,6 +150,7 @@ WebViewPermissionHelper::WebViewPermissionHelper(WebViewGuest* web_view_guest)
     : content::WebContentsObserver(web_view_guest->web_contents()),
       next_permission_request_id_(guest_view::kInstanceIDNone),
       web_view_guest_(web_view_guest),
+      default_media_access_permission_(false),
       weak_factory_(this) {
       web_view_permission_helper_delegate_.reset(
           ExtensionsAPIClient::Get()->CreateWebViewPermissionHelperDelegate(
@@ -202,7 +203,7 @@ void WebViewPermissionHelper::RequestMediaAccessPermission(
                  weak_factory_.GetWeakPtr(),
                  request,
                  callback),
-      false /* allowed_by_default */);
+      default_media_access_permission_);
 }
 
 bool WebViewPermissionHelper::CheckMediaAccessPermission(

extensions/browser/guest_view/web_view/web_view_permission_helper.h

@@ -119,6 +119,10 @@ class WebViewPermissionHelper
 
   WebViewGuest* web_view_guest() { return web_view_guest_; }
 
+  void set_default_media_access_permission(bool allow_media_access) {
+    default_media_access_permission_ = allow_media_access;
+  }
+
  private:
   void OnMediaPermissionResponse(const content::MediaStreamRequest& request,
                                  const content::MediaResponseCallback& callback,
@@ -142,6 +146,8 @@ class WebViewPermissionHelper
 
   WebViewGuest* const web_view_guest_;
 
+  bool default_media_access_permission_;
+
   base::WeakPtrFactory<WebViewPermissionHelper> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebViewPermissionHelper);