Port update_engine_client ResetStatus command to lib

This is the first step in getting update_engine_client completely off of
direct DBus calls

Test: Ran --reset_status command and verified update_engine received the
      signal.
Bug: 26233663
Signed-off-by: Casey Dahlin <sadmac@google.com>

Change-Id: Iac54d890fd796f91a7813755d6061cf468255347
diff --git a/client_library/client_impl.cc b/client_library/client_impl.cc
index 84ca184..3dba873 100644
--- a/client_library/client_impl.cc
+++ b/client_library/client_impl.cc
@@ -66,6 +66,10 @@
   return StringToUpdateStatus(status_as_string, out_update_status);
 }
 
+bool UpdateEngineClientImpl::ResetStatus() {
+  return proxy_->ResetStatus(nullptr);
+}
+
 bool UpdateEngineClientImpl::SetTargetChannel(const string& in_target_channel) {
   return proxy_->SetChannel(
       in_target_channel,
diff --git a/client_library/client_impl.h b/client_library/client_impl.h
index e6194d2..912449f 100644
--- a/client_library/client_impl.h
+++ b/client_library/client_impl.h
@@ -44,6 +44,8 @@
                  std::string* out_new_version,
                  int64_t* out_new_size) override;
 
+  bool ResetStatus() override;
+
   bool SetTargetChannel(const std::string& target_channel) override;
 
   bool GetTargetChannel(std::string* out_channel) override;
diff --git a/client_library/include/update_engine/client.h b/client_library/include/update_engine/client.h
index b3cef66..3406ca6 100644
--- a/client_library/include/update_engine/client.h
+++ b/client_library/include/update_engine/client.h
@@ -66,6 +66,9 @@
                          std::string* out_new_version,
                          int64_t* out_new_size) = 0;
 
+  // Resets the status of the Update Engine
+  virtual bool ResetStatus() = 0;
+
   // Changes the current channel of the device to the target channel.
   virtual bool SetTargetChannel(const std::string& target_channel) = 0;