Reland [Mojo Video Capture] Hook up video capture service behind a feature flag

content/public/app/mojo/content_browser_manifest.json

 {
   "name": "content_browser",
   "display_name": "Content (browser process)",
   "interface_provider_specs": {
     "service_manager:connector": {
       "provides": {
         "gpu": [
           "content::mojom::FieldTrialRecorder",
           "media::mojom::AndroidOverlayProvider"
         ],
@@ skipping 66 matching lines @@
           "service_manager:instance_name",
           "service_manager:service_manager",
           "service_manager:user_id"
         ],
         "shape_detection": [
           "barcode_detection",
           "face_detection",
           "text_detection"
 
         ],
-        "resource_coordinator": [ "coordination_unit" ]
+        "resource_coordinator": [ "coordination_unit" ],
+        "video_capture": [ "capture" ]
       }
     },
     "navigation:frame": {
       "provides": {
         "renderer": [
           // TODO(beng): these belong in //chrome's overlay, but there are some
           // issues with mash browser_tests's manifest config that make this
           // impossible this week. Remove once sky/ken fix this.
           "autofill::mojom::AutofillDriver",
           "autofill::mojom::PasswordManagerDriver",
@@ skipping 19 matching lines @@
           "payments::mojom::PaymentRequest",
           "ui::mojom::Gpu"
         ]
       },
       "requires": {
         "content_renderer": [ "browser" ]
       }
     }
   }
 }