Remove const qualifier from function return type

components/copresence/rpc/rpc_handler_unittest.cc

Index: components/copresence/rpc/rpc_handler_unittest.cc
diff --git a/components/copresence/rpc/rpc_handler_unittest.cc b/components/copresence/rpc/rpc_handler_unittest.cc
index 3737eaf15d3001559cbd015d04d887ec8979df18..dabb4a2f24abb7c1b1282016961605589bc95527 100644
--- a/components/copresence/rpc/rpc_handler_unittest.cc
+++ b/components/copresence/rpc/rpc_handler_unittest.cc
@@ -75,11 +75,11 @@ class RpcHandlerTest : public testing::Test, public CopresenceDelegate {
     return nullptr;
   }
 
-  const std::string GetPlatformVersionString() const override {
+  std::string GetPlatformVersionString() const override {
     return kChromeVersion;
   }
 
-  const std::string GetAPIKey(const std::string& app_id) const override {
+  std::string GetAPIKey(const std::string& app_id) const override {
     return app_id + " API Key";
   }
 
@@ -92,7 +92,7 @@ class RpcHandlerTest : public testing::Test, public CopresenceDelegate {
     return nullptr;
   }
 
-  const std::string GetDeviceId(bool authenticated) override {
+  std::string GetDeviceId(bool authenticated) override {
     return device_id_by_auth_state_[authenticated];
   }