libweave: Remove use of chromeos::Blob and chromeos::SecureBlob

Replaced with std::vector<uint8_t>

BUG=brillo:1257
TEST=`FEATURES=test emerge-gizmo libweave buffet`

Change-Id: I4ba2c23d84cb50815da056b1d75d322d8b365846
Reviewed-on: https://chromium-review.googlesource.com/293611
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
diff --git a/buffet/webserv_client.h b/buffet/webserv_client.h
index d7b5433..8457d8b 100644
--- a/buffet/webserv_client.h
+++ b/buffet/webserv_client.h
@@ -45,7 +45,7 @@
                          const OnRequestCallback& callback) override;
   uint16_t GetHttpPort() const override;
   uint16_t GetHttpsPort() const override;
-  const chromeos::Blob& GetHttpsCertificateFingerprint() const override;
+  const std::vector<uint8_t>& GetHttpsCertificateFingerprint() const override;
 
  private:
   void OnRequest(const OnRequestCallback& callback,
@@ -65,7 +65,7 @@
 
   uint16_t http_port_{0};
   uint16_t https_port_{0};
-  chromeos::Blob certificate_;
+  std::vector<uint8_t> certificate_;
 
   std::vector<OnStateChangedCallback> on_state_changed_callbacks_;