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 418 matching lines @@
       m_placeholderOption = PlaceholderOption::DoNotReloadPlaceholder;
     } else {
       m_placeholderOption = PlaceholderOption::ReloadPlaceholderOnDecodeError;
     }
   }
 }
 
 bool ImageResource::shouldShowPlaceholder() const {
   switch (m_placeholderOption) {
     case PlaceholderOption::ShowAndReloadPlaceholderAlways:
+    case PlaceholderOption::ShowAndDoNotReloadPlaceholder:
       return true;
     case PlaceholderOption::ReloadPlaceholderOnDecodeError:
     case PlaceholderOption::DoNotReloadPlaceholder:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 bool ImageResource::shouldReloadBrokenPlaceholder() const {
   switch (m_placeholderOption) {
     case PlaceholderOption::ShowAndReloadPlaceholderAlways:
       return errorOccurred();
     case PlaceholderOption::ReloadPlaceholderOnDecodeError:
       return getStatus() == ResourceStatus::DecodeError;
+    case PlaceholderOption::ShowAndDoNotReloadPlaceholder:
     case PlaceholderOption::DoNotReloadPlaceholder:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 static bool isLoFiImage(const ImageResource& resource) {
   if (!(resource.resourceRequest().previewsState() &
         WebURLRequest::ServerLoFiOn)) {
@@ skipping 17 matching lines @@
 
   // Prevent clients and observers from being notified of completion while the
   // reload is being scheduled, so that e.g. canceling an existing load in
   // progress doesn't cause clients and observers to be notified of completion
   // prematurely.
   DCHECK(!m_isSchedulingReload);
   m_isSchedulingReload = true;
 
   setCachePolicyBypassingCache();
 
+  WebURLRequest::PreviewsState previewsState =

[sclittle, 2017/04/06 21:58:06]

nit: maybe name this "previewsStateBeforeReload" or "oldPreviewsState" or
something to differentiate it from the current previews state of the request?

[Raj, 2017/05/03 07:05:18]

Renamed as old_previews_state as per new naming convention.

+      resourceRequest().previewsState();
+
   setPreviewsStateNoTransform();
 
   if (m_placeholderOption != PlaceholderOption::DoNotReloadPlaceholder)
     clearRangeRequestHeader();
-  m_placeholderOption = PlaceholderOption::DoNotReloadPlaceholder;
+
+  if (previewsState & WebURLRequest::ClientLoFiOn) {

[sclittle, 2017/04/06 21:58:06]

Chrome should still show the full image if the user manually reloaded the image,
e.g. by clicking "Show Original" on the previews infobar.

I think |policy| is |kReloadAlways| in that case, so ImageResource could just
check that here.

[Raj, 2017/05/03 07:05:18]

Thanks. Added this check.

+    m_placeholderOption = PlaceholderOption::ShowAndDoNotReloadPlaceholder;
+  } else {
+    m_placeholderOption = PlaceholderOption::DoNotReloadPlaceholder;
+  }

[sclittle, 2017/04/06 21:58:06]

Could you add tests for the new behavior you've added?

 
   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::ClearImageAndNotifyObservers,
@@ skipping 86 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(allDataReceived);
   }
 }
 
 }  // namespace blink