Remove the -webkit-fullscreen-volume-* pseudos, they're dead code.

third_party/WebKit/Source/core/html/shadow/SliderThumbElement.cpp

Index: third_party/WebKit/Source/core/html/shadow/SliderThumbElement.cpp
diff --git a/third_party/WebKit/Source/core/html/shadow/SliderThumbElement.cpp b/third_party/WebKit/Source/core/html/shadow/SliderThumbElement.cpp
index ddd3f9b913ce6da687e1410466588f7918834491..d5ca0fc2a5c53c3e520fcf5f23f6fd2f6cd929ba 100644
--- a/third_party/WebKit/Source/core/html/shadow/SliderThumbElement.cpp
+++ b/third_party/WebKit/Source/core/html/shadow/SliderThumbElement.cpp
@@ -302,8 +302,6 @@ const AtomicString& SliderThumbElement::shadowPseudoId() const {
     case MediaSliderThumbPart:
     case MediaVolumeSliderPart:
     case MediaVolumeSliderThumbPart:
-    case MediaFullscreenVolumeSliderPart:
-    case MediaFullscreenVolumeSliderThumbPart:
       return mediaSliderThumbShadowPartId();
     default:
       return sliderThumbShadowPartId();
@@ -434,8 +432,6 @@ const AtomicString& SliderContainerElement::shadowPseudoId() const {
     case MediaSliderThumbPart:
     case MediaVolumeSliderPart:
     case MediaVolumeSliderThumbPart:
-    case MediaFullscreenVolumeSliderPart:
-    case MediaFullscreenVolumeSliderThumbPart:
       return mediaSliderContainer;
     default:
       return sliderContainer;