[fuchsia] Add console log level control to ApplicationConfig

Use will follow in a separate CL.

Bug: 1145025
Change-Id: Ib0d302120256c080f73db36d66c29ad60ab4d14f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2516246
Commit-Queue: David Dorwin <ddorwin@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823591}

fuchsia/fidl/cast/application_config.fidl

@@ -4,6 +4,7 @@
 
 library chromium.cast;
 
+using fuchsia.diagnostics;
 using fuchsia.ui.gfx;
 using fuchsia.web;
 
@@ -38,6 +39,12 @@ resource table ApplicationConfig {
 
   /// List of the web permissions that should be granted to the application.
   9: vector<fuchsia.web.PermissionDescriptor> permissions;
+
+  /// The initial minimum severity of `console` logs that will be logged to the
+  /// [`fuchsia.logger/LogSink`] configured for this application. If not set, no
+  /// messages will be logged.
+  // TODO(crbug.com/1088094): Deprecate once there is another mechanism.
+  10: fuchsia.diagnostics.Severity initial_min_console_log_severity;
 };
 
 /// Service interface for working with application configurations.