Remove the use of url::Origin from user_media_processor.cc

Apart from the fact that it is not being used anywhere, it is
also an inconvenience, since this file is in the process of being
migrated to Blink [1], where the header is banned.

This CL cleans it up.

[1] https://crrev.com/c/1731644

BUG=704136
R=guidou@chromium.org, haraken@chromium.org

Change-Id: Ie8626c1d139733787b867293c46d768d1ea66eee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1731872
Auto-Submit: Antonio Gomes <tonikitoo@igalia.com>
Commit-Queue: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683755}

content/renderer/media/stream/user_media_processor.cc

@@ -47,7 +47,6 @@
 #include "third_party/blink/public/web/modules/mediastream/processed_local_audio_source.h"
 #include "third_party/blink/public/web/modules/mediastream/web_media_stream_device_observer.h"
 #include "ui/gfx/geometry/size.h"
-#include "url/origin.h"
 
 namespace content {
 
@@ -317,8 +316,6 @@ class UserMediaProcessor::RequestInfo
     return request_->is_processing_user_gesture;
   }
 
-  const url::Origin& security_origin() const { return security_origin_; }
-
  private:
   void OnTrackStarted(blink::WebPlatformMediaStreamSource* source,
                       MediaStreamRequestResult result,
@@ -337,7 +334,6 @@ class UserMediaProcessor::RequestInfo
   bool is_video_content_capture_ = false;
   blink::WebMediaStream web_stream_;
   StreamControls stream_controls_;
-  const url::Origin security_origin_;
   ResourcesReady ready_callback_;
   MediaStreamRequestResult request_result_ = MediaStreamRequestResult::OK;
   blink::WebString request_result_name_;
@@ -355,7 +351,6 @@ class UserMediaProcessor::RequestInfo
 UserMediaProcessor::RequestInfo::RequestInfo(
     std::unique_ptr<UserMediaRequestInfo> request)
     : request_(std::move(request)),
-      security_origin_(url::Origin(request_->web_request.GetSecurityOrigin())),
       request_result_name_("") {}
 
 void UserMediaProcessor::RequestInfo::StartAudioTrack(