[Mojo Video Capture] Cleanup naming of classes/files in services/video_capture

services/video_capture/public/interfaces/capture_settings.mojom

 // 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.
 
 module video_capture.mojom;
 
 import "media/capture/mojo/video_capture_types.mojom";
 import "ui/gfx/geometry/mojo/geometry.mojom";
 
 // This format implies a pixel format of I420
 // and a storage type of Mojo Shared Memory.
-struct VideoCaptureFormat {
+struct I420CaptureFormat {
   gfx.mojom.Size frame_size;
   float frame_rate;
 };
 
-struct VideoCaptureSettings {
-  VideoCaptureFormat format;
+struct CaptureSettings {
+  I420CaptureFormat format;
   media.mojom.ResolutionChangePolicy resolution_change_policy;
   media.mojom.PowerLineFrequency power_line_frequency;
 };