Clean up textTrackDisplayElement utility function

third_party/WebKit/LayoutTests/media/media-controls.js

 var captionsButtonElement;
 var captionsButtonCoordinates;
 
 // As specified in mediaControls.css, this is how long it takes to fade out controls
 const controlsFadeOutDurationMs = 300;
 
 // The timeout for the hide-after-no-mouse-movement behavior. Defined (and
 // should mirror) the value 'timeWithoutMouseMovementBeforeHidingMediaControls'
 // in MediaControls.cpp.
 const controlsMouseMovementTimeoutMs = 3000;
@@ skipping 55 matching lines @@
     var button = mediaControlsButton(element, id);
     var buttonBoundingRect = button.getBoundingClientRect();
     return new Array(buttonBoundingRect.width, buttonBoundingRect.height);
 }
 
 function textTrackContainerElement(parentElement) {
     return mediaControlsElement(internals.shadowRoot(parentElement).firstChild,
         "-webkit-media-text-track-container");
 }
 
-function textTrackCueDisplayElement(parentElement) {
-    var containerElement = textTrackContainerElement(parentElement);
-    return mediaControlsElement(containerElement.firstChild, "-webkit-media-text-track-display");
-}
-
 function textTrackCueElementByIndex(parentElement, cueIndex) {
-    var displayElement = textTrackCueDisplayElement(parentElement);
+    var displayElement = textTrackDisplayElement(parentElement);
     if (displayElement) {
         for (i = 0; i < cueIndex; i++)
             displayElement = displayElement.nextSibling;
     }
 
     return displayElement;
 }
 
 function textTrackRegionElement(parentElement)
 {
     var containerElement = textTrackContainerElement(parentElement);
     return mediaControlsElement(containerElement.firstChild, "-webkit-media-text-track-region");
 }
 
 function textTrackRegionContainerElement(parentElement)
 {
     var containerElement = textTrackContainerElement(parentElement);
     return mediaControlsElement(containerElement.firstChild, "-webkit-media-text-track-region-container");
 }
 
-// TODO(srirama.m): Phase out the uses of this function and
-// replace with more specific functions at each call site.
-function textTrackDisplayElement(parentElement, id, cueNumber)
+function textTrackDisplayElement(parentElement)
 {
     var containerElement = textTrackContainerElement(parentElement);
-
-    if (!containerElement)
-        throw "Failed to find text track container element";
-
-    if (!id)
-        return containerElement;
-
-    var controlID = id;
-    if (controlID != 'cue')
-        controlID = "-webkit-media-text-track-" + id;
-
-    var displayElement = mediaControlsElement(containerElement.firstChild, controlID);
-    if (!displayElement)
-        throw "No text track cue with display id '" + controlID + "' is currently visible";
-
-    if (cueNumber) {
-        for (i = 0; i < cueNumber; i++)
-            displayElement = displayElement.nextSibling;
-
-        if (!displayElement)
-            throw "There are not " + cueNumber + " text track cues visible";
-    }
-
-    return displayElement;
+    return mediaControlsElement(containerElement.firstChild, "-webkit-media-text-track-display");
 }
 
 function isClosedCaptionsButtonVisible(currentMediaElement)
 {
     var captionsButtonElement = mediaControlsButton(currentMediaElement, "toggle-closed-captions-button");
     var captionsButtonCoordinates = mediaControlsButtonCoordinates(currentMediaElement, "toggle-closed-captions-button");
 
     if (!captionsButtonElement.disabled
         && captionsButtonCoordinates[0] > 0
         && captionsButtonCoordinates[1] > 0) {
@@ skipping 53 matching lines @@
         throw "The media will end before the controls have been hidden";
 
     setTimeout(func, hideTimeoutMs);
 }
 
 function hasFullscreenButton(element)
 {
     var size = mediaControlsButtonDimensions(element, "fullscreen-button");
     return size[0] > 0 && size[1] > 0;
 }