[gold] Remove Clear from expstore interface

Is likely unneeded. We can always clean things up with a cronjob if
really necessary.

Bug: skia:9090
Change-Id: Ic8c90d1ab5e2b281f297389f4d9599a3e6d2afcc
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/217937
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
diff --git a/golden/go/expstorage/ds_expstore/ds_expstore_test.go b/golden/go/expstorage/ds_expstore/ds_expstore_test.go
index 1cf9d8c..276b4b5e 100644
--- a/golden/go/expstorage/ds_expstore/ds_expstore_test.go
+++ b/golden/go/expstorage/ds_expstore/ds_expstore_test.go
@@ -41,7 +41,7 @@
 	testCloudExpstoreClear(t, cloudStore)
 }
 
-func testCloudExpstoreClear(t *testing.T, cloudStore expstorage.ExpectationsStore) {
+func testCloudExpstoreClear(t *testing.T, cloudStore *DSExpStore) {
 	// Make sure the clear works.
 	ctx := context.Background()
 	assert.NoError(t, cloudStore.Clear(ctx))
@@ -70,7 +70,7 @@
 	issueID := int64(1234567)
 	issueStore := issueStoreFactory(issueID)
 	testExpectationStore(t, issueStore, masterEventBus, issueID, expstorage.EV_TRYJOB_EXP_CHANGED)
-	testCloudExpstoreClear(t, issueStore)
+	testCloudExpstoreClear(t, issueStore.(*DSExpStore))
 }
 
 // initDS initializes the datastore for testing.
diff --git a/golden/go/expstorage/types.go b/golden/go/expstorage/types.go
index 739a6d9..f29036c 100644
--- a/golden/go/expstorage/types.go
+++ b/golden/go/expstorage/types.go
@@ -52,12 +52,6 @@
 	// A new entry is added to the log with a reference to the change that was
 	// undone.
 	UndoChange(ctx context.Context, changeID int64, userID string) (types.Expectations, error)
-
-	// Clear deletes all expectations in this ExpectationsStore. This is mostly
-	// used for testing, but also to delete the expectations for a Gerrit issue.
-	// See the tryjobstore package.
-	// TODO(kjlubick): I think this should be removed
-	Clear(ctx context.Context) error
 }
 
 // TriageDetails represents one changed digest and the label that was
diff --git a/golden/go/mocks/ExpectationsStore.go b/golden/go/mocks/ExpectationsStore.go
index 318853f..f4214b7 100644
--- a/golden/go/mocks/ExpectationsStore.go
+++ b/golden/go/mocks/ExpectationsStore.go
@@ -26,20 +26,6 @@
 	return r0
 }
 
-// Clear provides a mock function with given fields: ctx
-func (_m *ExpectationsStore) Clear(ctx context.Context) error {
-	ret := _m.Called(ctx)
-
-	var r0 error
-	if rf, ok := ret.Get(0).(func(context.Context) error); ok {
-		r0 = rf(ctx)
-	} else {
-		r0 = ret.Error(0)
-	}
-
-	return r0
-}
-
 // Get provides a mock function with given fields:
 func (_m *ExpectationsStore) Get() (types.Expectations, error) {
 	ret := _m.Called()
diff --git a/golden/go/tryjobstore/tryjobstore.go b/golden/go/tryjobstore/tryjobstore.go
index bf5a3b1..5494f83 100644
--- a/golden/go/tryjobstore/tryjobstore.go
+++ b/golden/go/tryjobstore/tryjobstore.go
@@ -11,6 +11,7 @@
 	"go.skia.org/infra/go/ds"
 	"go.skia.org/infra/go/eventbus"
 	"go.skia.org/infra/go/gevent"
+	"go.skia.org/infra/go/skerr"
 	"go.skia.org/infra/go/sklog"
 	"go.skia.org/infra/go/util"
 	"go.skia.org/infra/golden/go/expstorage"
@@ -233,25 +234,13 @@
 // DeleteIssue implements the TryjobStore interface.
 func (c *cloudTryjobStore) DeleteIssue(issueID int64) error {
 	ctx := context.TODO()
-	key := c.getIssueKey(issueID)
 
-	var egroup errgroup.Group
-
-	egroup.Go(func() error {
-		// Delete any tryjobs that are still there.
-		return c.deleteTryjobsForIssue(issueID)
-	})
-
-	// Remove the expectations for this issue.
-	egroup.Go(func() error {
-		return c.expStoreFactory(issueID).Clear(ctx)
-	})
-
-	// Make sure all dependents are deleted.
-	if err := egroup.Wait(); err != nil {
-		return err
+	// Delete any tryjobs that are still there.
+	if err := c.deleteTryjobsForIssue(issueID); err != nil {
+		return skerr.Fmt("could not delete tryjobs for issue %d: %s", issueID, err)
 	}
 
+	key := c.getIssueKey(issueID)
 	// Delete the entity.
 	return c.client.Delete(ctx, key)
 }