Use the return value to signal success for VTTParser helpers

Source/core/html/track/vtt/VTTRegion.cpp

 /*
  * Copyright (C) 2013 Google Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 217 matching lines @@
     if (setting == scrollKeyword)
         return Scroll;
 
     return None;
 }
 
 void VTTRegion::parseSettingValue(RegionSetting setting, const String& value)
 {
     DEFINE_STATIC_LOCAL(const AtomicString, scrollUpValueKeyword, ("up", AtomicString::ConstructFromLiteral));
 
-    bool isValidSetting;
-    String numberAsString;
-    int number;
-    FloatPoint anchorPosition;
-
     switch (setting) {
     case Id:
         if (value.find("-->") == kNotFound)
             m_id = value;
         break;
-    case Width:
-        number = VTTParser::parseFloatPercentageValue(value, isValidSetting);
-        if (isValidSetting)
-            m_width = number;
+    case Width: {
+        float floatWidth;
+        if (VTTParser::parseFloatPercentageValue(value, floatWidth))
+            m_width = floatWidth;
         else
             WTF_LOG(Media, "VTTRegion::parseSettingValue, invalid Width");
         break;
+    }
     case Height: {
         unsigned position = 0;
+        int number;
         if (VTTParser::collectDigitsToInt(value, &position, number) && position == value.length())
             m_heightInLines = number;
         else
             WTF_LOG(Media, "VTTRegion::parseSettingValue, invalid Height");
         break;
     }
     case RegionAnchor:
-        anchorPosition = VTTParser::parseFloatPercentageValuePair(value, ',', isValidSetting);
-        if (isValidSetting)
-            m_regionAnchor = anchorPosition;
-        else
+        if (!VTTParser::parseFloatPercentageValuePair(value, ',', m_regionAnchor))
             WTF_LOG(Media, "VTTRegion::parseSettingValue, invalid RegionAnchor");
         break;
     case ViewportAnchor:
-        anchorPosition = VTTParser::parseFloatPercentageValuePair(value, ',', isValidSetting);
-        if (isValidSetting)
-            m_viewportAnchor = anchorPosition;
-        else
+        if (!VTTParser::parseFloatPercentageValuePair(value, ',', m_viewportAnchor))
             WTF_LOG(Media, "VTTRegion::parseSettingValue, invalid ViewportAnchor");
         break;
     case Scroll:
         if (value == scrollUpValueKeyword)
             m_scroll = true;
         else
             WTF_LOG(Media, "VTTRegion::parseSettingValue, invalid Scroll");
         break;
     case None:
         break;
@@ skipping 181 matching lines @@
 
 void VTTRegion::scrollTimerFired(Timer<VTTRegion>*)
 {
     WTF_LOG(Media, "VTTRegion::scrollTimerFired");
 
     stopTimer();
     displayLastVTTCueBox();
 }
 
 } // namespace WebCore