Show image placeholders on dimension decode error

third_party/WebKit/Source/core/loader/resource/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 443 matching lines @@
       placeholder_option_ = PlaceholderOption::kDoNotReloadPlaceholder;
     } else {
       placeholder_option_ = PlaceholderOption::kReloadPlaceholderOnDecodeError;
     }
   }
 }
 
 bool ImageResource::ShouldShowPlaceholder() const {
   switch (placeholder_option_) {
     case PlaceholderOption::kShowAndReloadPlaceholderAlways:
+    case PlaceholderOption::kShowAndDoNotReloadPlaceholder:
       return true;
     case PlaceholderOption::kReloadPlaceholderOnDecodeError:
     case PlaceholderOption::kDoNotReloadPlaceholder:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 bool ImageResource::ShouldReloadBrokenPlaceholder() const {
   switch (placeholder_option_) {
     case PlaceholderOption::kShowAndReloadPlaceholderAlways:
       return ErrorOccurred();
     case PlaceholderOption::kReloadPlaceholderOnDecodeError:
       return GetStatus() == ResourceStatus::kDecodeError;
+    case PlaceholderOption::kShowAndDoNotReloadPlaceholder:
     case PlaceholderOption::kDoNotReloadPlaceholder:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 static bool IsLoFiImage(const ImageResource& resource) {
   if (resource.IsLoaded()) {
     return resource.GetResponse()
@@ skipping 22 matching lines @@
   // progress doesn't cause clients and observers to be notified of completion
   // prematurely.
   DCHECK(!is_scheduling_reload_);
   is_scheduling_reload_ = true;
 
   SetCachePolicyBypassingCache();
 
   // The reloaded image should not use any previews transformations.
   WebURLRequest::PreviewsState previews_state_for_reload =
       WebURLRequest::kPreviewsNoTransform;
+  WebURLRequest::PreviewsState old_previews_state =
+      GetResourceRequest().GetPreviewsState();
 
   if (policy == kReloadIfNeeded && (GetResourceRequest().GetPreviewsState() &
                                     WebURLRequest::kClientLoFiOn)) {
     // If the image attempted to use Client LoFi, but encountered a decoding
     // error and is being automatically reloaded, then also set the appropriate
     // PreviewsState bit for that. This allows the embedder to count the
     // bandwidth used for this reload against the data savings of the initial
     // response.
     previews_state_for_reload |= WebURLRequest::kClientLoFiAutoReload;
   }
   SetPreviewsState(previews_state_for_reload);
 
   if (placeholder_option_ != PlaceholderOption::kDoNotReloadPlaceholder)
     ClearRangeRequestHeader();
-  placeholder_option_ = PlaceholderOption::kDoNotReloadPlaceholder;
+
+  if (old_previews_state & WebURLRequest::kClientLoFiOn &&
+      policy != kReloadAlways) {
+    placeholder_option_ = PlaceholderOption::kShowAndDoNotReloadPlaceholder;
+  } else {
+    placeholder_option_ = PlaceholderOption::kDoNotReloadPlaceholder;
+  }
 
   if (IsLoading()) {
     Loader()->Cancel();
     // Canceling the loader causes error() to be called, which in turn calls
     // clear() and notifyObservers(), so there's no need to call these again
     // here.
   } else {
     ClearData();
     SetEncodedSize(0);
     UpdateImage(nullptr, ImageResourceContent::kClearImageAndNotifyObservers,
@@ skipping 88 matching lines @@
     //    reloading in Step 3 due to notifyObservers()'s
     //    schedulingReloadOrShouldReloadBrokenPlaceholder() check.
     // 3. reloadIfLoFiOrPlaceholderImage() is called via ResourceFetcher
     //    (a) via didFinishLoading() called in decodeError(), or
     //    (b) after returning ImageResource::updateImage().
     DecodeError(all_data_received);
   }
 }
 
 }  // namespace blink