FontCachePurgePreventer is needed when computing MinPreferredWidth

third_party/WebKit/Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 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 3274 matching lines @@
         ->UpdateLifecycleToCompositingCleanPlusScrolling();
 
   Document* document = page_->MainFrame()->IsLocalFrame()
                            ? page_->DeprecatedLocalMainFrame()->GetDocument()
                            : nullptr;
   if (!document || document->GetLayoutViewItem().IsNull() ||
       !document->documentElement() ||
       !document->documentElement()->GetLayoutBox())
     return WebSize();
 
+  // Needed for computing MinPreferredWidth.
+  FontCachePurgePreventer fontCachePurgePreventer;
   int width_scaled = document->GetLayoutViewItem()
                          .MinPreferredLogicalWidth()
                          .Round();  // Already accounts for zoom.
   int height_scaled =
       document->documentElement()->GetLayoutBox()->ScrollHeight().Round();
   return IntSize(width_scaled, height_scaled);
 }
 
 float WebViewImpl::DefaultMinimumPageScaleFactor() const {
   return GetPageScaleConstraintsSet().DefaultConstraints().minimum_scale;
@@ skipping 855 matching lines @@
   if (focused_frame->LocalFrameRoot() != MainFrameImpl()->GetFrame())
     return nullptr;
   return focused_frame;
 }
 
 LocalFrame* WebViewImpl::FocusedLocalFrameAvailableForIme() const {
   return ime_accept_events_ ? FocusedLocalFrameInWidget() : nullptr;
 }
 
 }  // namespace blink