Oilpan: fix build after r198661.

Source/core/html/track/AutomaticTrackSelection.cpp

Index: Source/core/html/track/AutomaticTrackSelection.cpp
diff --git a/Source/core/html/track/AutomaticTrackSelection.cpp b/Source/core/html/track/AutomaticTrackSelection.cpp
index 1a9dd43693ca1b66d1df0d085438896f3aaf24e2..97a886299c5266274fc6c8acd74a76b126e752ed 100644
--- a/Source/core/html/track/AutomaticTrackSelection.cpp
+++ b/Source/core/html/track/AutomaticTrackSelection.cpp
@@ -123,8 +123,12 @@ void AutomaticTrackSelection::performAutomaticTextTrackSelection(const TrackGrou
     if (!trackToEnable && defaultTrack)
         trackToEnable = defaultTrack;
 
-    if (!trackToEnable && m_configuration.forceEnableSubtitleOrCaptionTrack && group.kind == TrackGroup::CaptionsAndSubtitles)
-        trackToEnable = fallbackTrack ? fallbackTrack : group.tracks[0];
+    if (!trackToEnable && m_configuration.forceEnableSubtitleOrCaptionTrack && group.kind == TrackGroup::CaptionsAndSubtitles) {
+        if (fallbackTrack)
+            trackToEnable = fallbackTrack;
+        else
+            trackToEnable = group.tracks[0];
+    }
 
     if (currentlyEnabledTracks.size()) {
         for (size_t i = 0; i < currentlyEnabledTracks.size(); ++i) {