WebLocalFrameImpl::printPage needs to ensure layout, style, and compositing are up-to-date

Source/web/WebLocalFrameImpl.cpp

 /*
  * Copyright (C) 2009 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 290 matching lines @@
         m_printedPageWidth = width;
         PrintContext::begin(m_printedPageWidth, height);
     }
 
     virtual float getPageShrink(int pageNumber) const
     {
         IntRect pageRect = m_pageRects[pageNumber];
         return m_printedPageWidth / pageRect.width();
     }
 
-    // Spools the printed page, a subrect of frame(). Skip the scale step.
-    // NativeTheme doesn't play well with scaling. Scaling is done browser side
-    // instead. Returns the scale to be applied.
-    // On Linux, we don't have the problem with NativeTheme, hence we let WebKit
-    // do the scaling and ignore the return value.
-    virtual float spoolPage(GraphicsContext& context, int pageNumber)
+    float spoolSinglePage(GraphicsContext& graphicsContext, int pageNumber)
     {
-        IntRect pageRect = m_pageRects[pageNumber];
-        float scale = m_printedPageWidth / pageRect.width();
-
-        context.save();
-#if OS(POSIX) && !OS(MACOSX)
-        context.scale(scale, scale);
-#endif
-        context.translate(static_cast<float>(-pageRect.x()), static_cast<float>(-pageRect.y()));
-        context.clip(pageRect);
-        frame()->view()->paintContents(&context, pageRect);
-        if (context.supportsURLFragments())
-            outputLinkedDestinations(context, frame()->document(), pageRect);
-        context.restore();
-        return scale;
+        // FIXME: Why is it ok to proceed without all the null checks that
+        // spoolAllPagesWithBoundaries does?
+        frame()->view()->updateLayoutAndStyleForPainting();
+        return spoolPage(graphicsContext, pageNumber);
     }
 
     void spoolAllPagesWithBoundaries(GraphicsContext& graphicsContext, const FloatSize& pageSizeInPixels)
     {
         if (!frame()->document() || !frame()->view() || !frame()->document()->renderView())
             return;
 
         frame()->view()->updateLayoutAndStyleForPainting();
 
         float pageHeight;
@@ skipping 27 matching lines @@
             float scale = getPageShrink(pageIndex);
             graphicsContext.scale(scale, scale);
 #endif
             spoolPage(graphicsContext, pageIndex);
             graphicsContext.restore();
 
             currentHeight += pageSizeInPixels.height() + 1;
         }
     }
 
+protected:
+    // Spools the printed page, a subrect of frame(). Skip the scale step.
+    // NativeTheme doesn't play well with scaling. Scaling is done browser side
+    // instead. Returns the scale to be applied.
+    // On Linux, we don't have the problem with NativeTheme, hence we let WebKit
+    // do the scaling and ignore the return value.
+    virtual float spoolPage(GraphicsContext& context, int pageNumber)
+    {
+        IntRect pageRect = m_pageRects[pageNumber];
+        float scale = m_printedPageWidth / pageRect.width();
+
+        context.save();
+#if OS(POSIX) && !OS(MACOSX)
+        context.scale(scale, scale);
+#endif
+        context.translate(static_cast<float>(-pageRect.x()), static_cast<float>(-pageRect.y()));
+        context.clip(pageRect);
+        frame()->view()->paintContents(&context, pageRect);
+        if (context.supportsURLFragments())
+            outputLinkedDestinations(context, frame()->document(), pageRect);
+        context.restore();
+        return scale;
+    }
+
 private:
     // Set when printing.
     float m_printedPageWidth;
 };
 
 // Simple class to override some of PrintContext behavior. This is used when
 // the frame hosts a plugin that supports custom printing. In this case, we
 // want to delegate all printing related calls to the plugin.
 class ChromePluginPrintContext FINAL : public ChromePrintContext {
 public:
@@ skipping 23 matching lines @@
     {
         m_printParams.printContentArea = IntRect(printRect);
         m_pageCount = m_plugin->printBegin(m_printParams);
     }
 
     virtual int pageCount() const
     {
         return m_pageCount;
     }
 
+protected:
     // Spools the printed page, a subrect of frame(). Skip the scale step.
     // NativeTheme doesn't play well with scaling. Scaling is done browser side
     // instead. Returns the scale to be applied.
     virtual float spoolPage(GraphicsContext& context, int pageNumber)
     {
         m_plugin->printPage(pageNumber, &context);
         return 1.0;
     }
 
 private:
@@ skipping 848 matching lines @@
     return m_printContext->getPageShrink(page);
 }
 
 float WebLocalFrameImpl::printPage(int page, WebCanvas* canvas)
 {
 #if ENABLE(PRINTING)
     ASSERT(m_printContext && page >= 0 && frame() && frame()->document());
 
     GraphicsContext graphicsContext(canvas);
     graphicsContext.setPrinting(true);
-    return m_printContext->spoolPage(graphicsContext, page);
+    return m_printContext->spoolSinglePage(graphicsContext, page);
 #else
     return 0;
 #endif
 }
 
 void WebLocalFrameImpl::printEnd()
 {
     ASSERT(m_printContext);
     m_printContext->end();
     m_printContext.clear();
@@ skipping 559 matching lines @@
 
 void WebLocalFrameImpl::invalidateAll() const
 {
     ASSERT(frame() && frame()->view());
     FrameView* view = frame()->view();
     view->invalidateRect(view->frameRect());
     invalidateScrollbar();
 }
 
 } // namespace blink