suggest: Support clearing the suggestions store.

This commit exposes `SuggestDb.clear()` as `SuggestStore.clear()`, and
ensures that it removes all icons in addition to suggestions and
metadata.

components/suggest/src/db.rs

@@ -212,9 +212,11 @@ impl SuggestDb {
         Ok(())
     }
 
+    /// Clears the database, removing all suggestions, icons, and metadata.
     pub fn clear(&self) -> Result<()> {
         self.conn.lock().unwrap().execute_batch(
             "DELETE FROM suggestions;
+             DELETE FROM icons;
              DELETE FROM meta;",
         )?;
         Ok(())

components/suggest/src/store.rs

@@ -202,6 +202,11 @@ impl SuggestStore {
 
         Ok(())
     }
+
+    pub fn clear(&self) -> Result<(), SuggestApiError> {
+        let writer = &self.dbs()?.writer;
+        Ok(writer.clear()?)
+    }
 }
 
 struct SuggestStoreDbs {

components/suggest/src/suggest.udl

@@ -44,4 +44,7 @@ interface SuggestStore {
 
     [Throws=SuggestApiError]
     void ingest([ByRef] IngestLimits limits);
+
+    [Throws=SuggestApiError]
+    void clear();
 };