merged branch tgabi333/di_minor_code_duplication (PR #8949)

This PR was merged into the master branch.

Discussion
----------

[DependencyInjection] remove code duplication from ContainerBuilder

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  |no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

Commits
-------

485fb15 [DependencyInjection] remove code duplication from ContainerBuilder

Author: fabpot

src/Symfony/Component/DependencyInjection/ContainerBuilder.php

@@ -305,11 +305,7 @@ public function loadFromExtension($extension, array $values = array())
      */
     public function addCompilerPass(CompilerPassInterface $pass, $type = PassConfig::TYPE_BEFORE_OPTIMIZATION)
     {
-        if (null === $this->compiler) {
-            $this->compiler = new Compiler();
-        }
-
-        $this->compiler->addPass($pass, $type);
+        $this->getCompiler()->addPass($pass, $type);
 
         $this->addObjectResource($pass);
 
@@ -325,11 +321,7 @@ public function addCompilerPass(CompilerPassInterface $pass, $type = PassConfig:
      */
     public function getCompilerPassConfig()
     {
-        if (null === $this->compiler) {
-            $this->compiler = new Compiler();
-        }
-
-        return $this->compiler->getPassConfig();
+        return $this->getCompiler()->getPassConfig();
     }
 
     /**
@@ -610,12 +602,10 @@ public function prependExtensionConfig($name, array $config)
      */
     public function compile()
     {
-        if (null === $this->compiler) {
-            $this->compiler = new Compiler();
-        }
+        $compiler = $this->getCompiler();
 
         if ($this->trackResources) {
-            foreach ($this->compiler->getPassConfig()->getPasses() as $pass) {
+            foreach ($compiler->getPassConfig()->getPasses() as $pass) {
                 $this->addObjectResource($pass);
             }
 
@@ -626,7 +616,7 @@ public function compile()
             }
         }
 
-        $this->compiler->compile($this);
+        $compiler->compile($this);
 
         $this->extensionConfigs = array();