Dont force http server implementation to have cert copy in vector

BUG:24267885
Change-Id: Ic9d0ffecb9ea6b4caf0836372fae6565637c289c
Reviewed-on: https://weave-review.googlesource.com/1272
Reviewed-by: Alex Vakulenko <avakulenko@google.com>

libweave/examples/ubuntu/event_http_server.cc

diff --git a/libweave/examples/ubuntu/event_http_server.cc b/libweave/examples/ubuntu/event_http_server.cc
index 4a7156a..8129c4f 100644
--- a/libweave/examples/ubuntu/event_http_server.cc
+++ b/libweave/examples/ubuntu/event_http_server.cc
@@ -212,8 +212,7 @@
   return 7781;
 }
 
-const std::vector<uint8_t>& HttpServerImpl::GetHttpsCertificateFingerprint()
-    const {
+std::vector<uint8_t> HttpServerImpl::GetHttpsCertificateFingerprint() const {
   return cert_fingerprint_;
 }
 

libweave/examples/ubuntu/event_http_server.h

diff --git a/libweave/examples/ubuntu/event_http_server.h b/libweave/examples/ubuntu/event_http_server.h
index 82c51dd..8be3716 100644
--- a/libweave/examples/ubuntu/event_http_server.h
+++ b/libweave/examples/ubuntu/event_http_server.h
@@ -32,7 +32,7 @@
                          const OnRequestCallback& callback) override;
   uint16_t GetHttpPort() const override;
   uint16_t GetHttpsPort() const override;
-  const std::vector<uint8_t>& GetHttpsCertificateFingerprint() const override;
+  std::vector<uint8_t> GetHttpsCertificateFingerprint() const override;
 
  private:
   void GenerateX509();

libweave/include/weave/provider/http_server.h

diff --git a/libweave/include/weave/provider/http_server.h b/libweave/include/weave/provider/http_server.h
index 44c3e1d..e1eb30d 100644
--- a/libweave/include/weave/provider/http_server.h
+++ b/libweave/include/weave/provider/http_server.h
@@ -41,8 +41,7 @@
 
   virtual uint16_t GetHttpPort() const = 0;
   virtual uint16_t GetHttpsPort() const = 0;
-  virtual const std::vector<uint8_t>& GetHttpsCertificateFingerprint()
-      const = 0;
+  virtual std::vector<uint8_t> GetHttpsCertificateFingerprint() const = 0;
 
  protected:
   virtual ~HttpServer() = default;

libweave/include/weave/provider/test/mock_http_server.h

diff --git a/libweave/include/weave/provider/test/mock_http_server.h b/libweave/include/weave/provider/test/mock_http_server.h
index c6fc755..95988ac 100644
--- a/libweave/include/weave/provider/test/mock_http_server.h
+++ b/libweave/include/weave/provider/test/mock_http_server.h
@@ -23,7 +23,7 @@
 
   MOCK_CONST_METHOD0(GetHttpPort, uint16_t());
   MOCK_CONST_METHOD0(GetHttpsPort, uint16_t());
-  MOCK_CONST_METHOD0(GetHttpsCertificateFingerprint, std::vector<uint8_t>&());
+  MOCK_CONST_METHOD0(GetHttpsCertificateFingerprint, std::vector<uint8_t>());
 };
 
 }  // namespace test

libweave/src/weave_unittest.cc

diff --git a/libweave/src/weave_unittest.cc b/libweave/src/weave_unittest.cc
index b6f9207..4eef7d4 100644
--- a/libweave/src/weave_unittest.cc
+++ b/libweave/src/weave_unittest.cc
@@ -200,7 +200,7 @@
     EXPECT_CALL(http_server_, GetHttpPort()).WillRepeatedly(Return(11));
     EXPECT_CALL(http_server_, GetHttpsPort()).WillRepeatedly(Return(12));
     EXPECT_CALL(http_server_, GetHttpsCertificateFingerprint())
-        .WillRepeatedly(ReturnRefOfCopy(std::vector<uint8_t>{1, 2, 3}));
+        .WillRepeatedly(Return(std::vector<uint8_t>{1, 2, 3}));
     EXPECT_CALL(http_server_, AddRequestHandler(_, _))
         .WillRepeatedly(
             Invoke([this](const std::string& path_prefix,