Update comments regarding image caching

third_party/WebKit/Source/core/fetch/ImageResource.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
@@ skipping 433 matching lines @@
     if (!image || image != m_image)
         return;
     notifyObservers(&rect);
 }
 
 bool ImageResource::currentFrameKnownToBeOpaque(const LayoutObject* layoutObject)
 {
     blink::Image* image = this->image();
     if (image->isBitmapImage()) {
         TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "PaintImage", "data", InspectorPaintImageEvent::data(layoutObject, *this));
-        // BitmapImage::currentFrameKnownToBeOpaque() conservatively returns true for uncached
-        // frames. To get an accurate answer, we pre-cache the current frame metadata.
+        // BitmapImage::currentFrameKnownToBeOpaque() conservatively returns false for uncached
+        // frames. To increase the change of an accurate answer, we pre-cache the current frame
+        // metadata.
         image->imageForCurrentFrame();
     }
     return image->currentFrameKnownToBeOpaque();
 }
 
 bool ImageResource::isAccessAllowed(SecurityOrigin* securityOrigin)
 {
     if (response().wasFetchedViaServiceWorker())
         return response().serviceWorkerResponseType() != WebServiceWorkerResponseTypeOpaque;
     if (!image()->currentFrameHasSingleSecurityOrigin())
         return false;
     if (passesAccessControlCheck(securityOrigin))
         return true;
     return !securityOrigin->taintsCanvas(response().url());
 }
 
 bool ImageResource::loadingMultipartContent() const
 {
     return m_loader && m_loader->loadingMultipartContent();
 }
 
 } // namespace blink