some lint + review comments

src/main/proto/wfa/measurement/reporting/v2alpha/BUILD.bazel

@@ -332,6 +332,7 @@ proto_library(
         "@com_google_googleapis//google/api:annotations_proto",
         "@com_google_googleapis//google/api:client_proto",
         "@com_google_googleapis//google/api:field_behavior_proto",
+        "@com_google_googleapis//google/api:field_info_proto",
         "@com_google_googleapis//google/api:resource_proto",
         "@com_google_googleapis//google/longrunning:operations_proto",
         "@com_google_protobuf//:timestamp_proto",

src/main/proto/wfa/measurement/reporting/v2alpha/basic_reports_service.proto

@@ -19,6 +19,7 @@ package wfa.measurement.reporting.v2alpha;
 import "google/api/annotations.proto";
 import "google/api/client.proto";
 import "google/api/field_behavior.proto";
+import "google/api/field_info.proto";
 import "google/api/resource.proto";
 import "google/longrunning/operations.proto";
 import "google/protobuf/timestamp.proto";
@@ -37,7 +38,7 @@ service BasicReports {
       post: "/v2alpha/{parent=measurementConsumers/*}/basicReports"
       body: "basicReport"
     };
-    option (google.api.method_signature) = "parent,basicReport";
+    option (google.api.method_signature) = "parent,basic_report,basic_report_id";
   }
 
   // Returns the `BasicReport` with the given resource key.
@@ -141,10 +142,12 @@ message CreateBasicReportRequest {
   string basic_report_id = 2 [(google.api.field_behavior) = REQUIRED];
 
   // The BasicReport to create.
-  BasicReport basic_report = 3;
+  BasicReport basic_report = 3 [(google.api.field_behavior) = REQUIRED];
 
   // A unique identifier for this request. Restricted to 36 ASCII characters.
   // A random UUID is recommended.
   // This request is only idempotent if a `request_id` is provided.
-  string request_id = 4;
+  string request_id = 4 [
+      (google.api.field_info).format = UUID4,
+      (google.api.field_behavior) = OPTIONAL];
 }

src/main/proto/wfa/measurement/reporting/v2alpha/page.proto

@@ -86,9 +86,10 @@ message PageMetricSpec {
   // filters that are associated with calculation spec is reported.
   bool population_size = 1 [(google.api.field_behavior) = IMMUTABLE];
 
-  // The set of basic metrics that can be computed for any aspect of the
-  // reporting_unit (e.g. the whole thing, a single component, intersections,
-  // etc.)
+  // Specifies the set of basic metrics that can be computed for any aspect of
+  // the reporting_unit (e.g. the whole thing, a single component, intersections,
+  // etc.). Each element specifies that a particular metric should be included
+  // in the report output.
   message BasicMetricSetSpec {
     // The reach
     bool reach = 1 [(google.api.field_behavior) = IMMUTABLE];