Trigger repaint on first paint only on pending stylesheet decrement.

third_party/WebKit/Source/core/paint/BlockPainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/BlockPainter.h"
 
 #include "core/editing/DragCaretController.h"
 #include "core/editing/FrameSelection.h"
 #include "core/frame/Settings.h"
 #include "core/layout/LayoutBlockFlow.h"
@@ skipping 223 matching lines @@
         overflowRect.move(-m_layoutBlock.scrolledContentOffset());
     }
     m_layoutBlock.flipForWritingMode(overflowRect);
     overflowRect.moveBy(adjustedPaintOffset);
     return paintInfo.cullRect().intersectsCullRect(overflowRect);
 }
 
 void BlockPainter::paintContents(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     // Avoid painting descendants of the root element when stylesheets haven't loaded. This eliminates FOUC.
-    // It's ok not to draw, because later on, when all the stylesheets do load, styleResolverChanged() on the Document
-    // will do a full paint invalidation.
+    // It's ok not to draw, because later on, when all the stylesheets do load, styleResolverMayHaveChanged()
+    // on Document will trigger a full paint invalidation.
     if (m_layoutBlock.document().didLayoutWithPendingStylesheets() && !m_layoutBlock.isLayoutView())
         return;
 
     if (m_layoutBlock.childrenInline()) {
         if (shouldPaintDescendantOutlines(paintInfo.phase))
             ObjectPainter(m_layoutBlock).paintInlineChildrenOutlines(paintInfo, paintOffset);
         else
             LineBoxListPainter(m_layoutBlock.lineBoxes()).paint(m_layoutBlock, paintInfo, paintOffset);
     } else {
         PaintInfo paintInfoForDescendants = paintInfo.forDescendants();
         m_layoutBlock.paintChildren(paintInfoForDescendants, paintOffset);
     }
 }
 
 } // namespace blink