init: clean up the SectionParser interface and Parser class

Remove the dependency on Action and Service from what should be a
generic Parser class.

Make ActionParser, ImportParser, and ServiceParser take a pointer to
their associated classes instead of accessing them through a
singleton.

Misc fixes to SectionParser Interface:
1) Make SectionParser::ParseLineSection() non-const as it always should
have been.
2) Use Rvalue references where appropriate
3) Remove extra std::string& filename in SectionParser::EndFile()
4) Only have SectionParser::ParseSection() as pure virtual

Document SectionParser.

Make ImportParser report the filename and line number of failed imports.

Make ServiceParser report the filename and line number of duplicated services.

Test: Boot bullhead

Change-Id: I86568a5b375fb4f27f4cb235ed1e37635f01d630
diff --git a/init/service.cpp b/init/service.cpp
index c0745e3..08d0a1d 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -877,11 +877,6 @@
 }
 
 void ServiceManager::AddService(std::unique_ptr<Service> service) {
-    Service* old_service = FindServiceByName(service->name());
-    if (old_service) {
-        LOG(ERROR) << "ignored duplicate definition of service '" << service->name() << "'";
-        return;
-    }
     services_.emplace_back(std::move(service));
 }
 
@@ -1095,7 +1090,7 @@
     }
 }
 
-bool ServiceParser::ParseSection(const std::vector<std::string>& args, const std::string& filename,
+bool ServiceParser::ParseSection(std::vector<std::string>&& args, const std::string& filename,
                                  int line, std::string* err) {
     if (args.size() < 3) {
         *err = "services must have a name and a program";
@@ -1108,19 +1103,24 @@
         return false;
     }
 
+    Service* old_service = service_manager_->FindServiceByName(name);
+    if (old_service) {
+        *err = "ignored duplicate definition of service '" + name + "'";
+        return false;
+    }
+
     std::vector<std::string> str_args(args.begin() + 2, args.end());
     service_ = std::make_unique<Service>(name, str_args);
     return true;
 }
 
-bool ServiceParser::ParseLineSection(const std::vector<std::string>& args, int line,
-                                     std::string* err) {
-    return service_ ? service_->ParseLine(args, err) : false;
+bool ServiceParser::ParseLineSection(std::vector<std::string>&& args, int line, std::string* err) {
+    return service_ ? service_->ParseLine(std::move(args), err) : false;
 }
 
 void ServiceParser::EndSection() {
     if (service_) {
-        ServiceManager::GetInstance().AddService(std::move(service_));
+        service_manager_->AddService(std::move(service_));
     }
 }