[cros-search-service] Add ClearIndex to mojom interface

This CL adds ClearIndex function to the mojom interface IndexProxy.

Bug: 1132170
Change-Id: Iaa1a3c2846bcc8c94bd758fa784e736b953e3a63
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2437835Reviewed-by: Jia Meng <jiameng@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Commit-Queue: Thanh Nguyen <thanhdng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812514}

chromeos/components/local_search_service/index_proxy.cc

@@ -50,5 +50,10 @@ void IndexProxy::Find(const base::string16& query,
   }
 }
 
+void IndexProxy::ClearIndex(ClearIndexCallback callback) {
+  index_->ClearIndex();
+  std::move(callback).Run();
+}
+
 }  // namespace local_search_service
 }  // namespace chromeos

chromeos/components/local_search_service/index_proxy.h

@@ -33,6 +33,7 @@ class IndexProxy : public mojom::IndexProxy {
   void Find(const base::string16& query,
             uint32_t max_results,
             FindCallback callback) override;
+  void ClearIndex(ClearIndexCallback callback) override;
 
  private:
   Index* const index_;

chromeos/components/local_search_service/mojom/local_search_service_proxy.mojom

@@ -53,4 +53,7 @@ interface IndexProxy {
   // code via a callback. |results| will be null if there is an error.
   Find(mojo_base.mojom.String16 query, uint32 max_results)
       => (ResponseStatus status, array<Result>? results);
+
+  // Clears all data stored by the index.
+  ClearIndex() => ();
 };