Revert of Add a FOUC painting test.

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 5c372f9119c7c0db03f2a24320cf53b9ae50fd4a..d6c9e8ae39f27940447b603a035a7fae50266572 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -339,7 +339,7 @@
 
 uint64_t Document::s_globalTreeVersion = 0;
 
-static bool s_threadedParsingEnabledForTesting = true;
+static bool s_threadedParsingEnabledForUnitTests = true;
 
 Document::WeakDocumentSet& Document::liveDocumentSet()
 {
@@ -2387,7 +2387,7 @@
 
     setCompatibilityMode(NoQuirksMode);
 
-    if (!threadedParsingEnabledForTesting())
+    if (!threadedParsingEnabledForUnitTestsOnly())
         parserSyncPolicy = ForceSynchronousParsing;
 
     m_parserSyncPolicy = parserSyncPolicy;
@@ -5233,14 +5233,14 @@
     adjustFloatRectForAbsoluteZoom(rect, layoutObject);
 }
 
-void Document::setThreadedParsingEnabledForTesting(bool enabled)
-{
-    s_threadedParsingEnabledForTesting = enabled;
-}
-
-bool Document::threadedParsingEnabledForTesting()
-{
-    return s_threadedParsingEnabledForTesting;
+void Document::setThreadedParsingEnabledForUnitTestsOnly(bool enabled)
+{
+    s_threadedParsingEnabledForUnitTests = enabled;
+}
+
+bool Document::threadedParsingEnabledForUnitTestsOnly()
+{
+    return s_threadedParsingEnabledForUnitTests;
 }
 
 bool Document::hasActiveParser()