Stop using controller as a variable name for FullscreenElementStack

Source/core/rendering/RenderFullScreen.cpp

Index: Source/core/rendering/RenderFullScreen.cpp
diff --git a/Source/core/rendering/RenderFullScreen.cpp b/Source/core/rendering/RenderFullScreen.cpp
index 484e9c38be8d8082b7dff63d339a5bf0418f58e3..875cfc8f54fd9c4de2f69b22120ea93bbc83b1d2 100644
--- a/Source/core/rendering/RenderFullScreen.cpp
+++ b/Source/core/rendering/RenderFullScreen.cpp
@@ -74,10 +74,10 @@ void RenderFullScreen::willBeDestroyed()
     }
 
     // RenderObjects are unretained, so notify the document (which holds a pointer to a RenderFullScreen)
-    // if it's RenderFullScreen is destroyed.
-    FullscreenElementStack& controller = FullscreenElementStack::from(document());
-    if (controller.fullScreenRenderer() == this)
-        controller.fullScreenRendererDestroyed();
+    // if its RenderFullScreen is destroyed.
+    FullscreenElementStack& fullscreen = FullscreenElementStack::from(document());
+    if (fullscreen.fullScreenRenderer() == this)
+        fullscreen.fullScreenRendererDestroyed();
 
     RenderFlexibleBox::willBeDestroyed();
 }