Show image placeholders on dimension decode error

third_party/WebKit/Source/core/loader/resource/ImageResource.cpp

Index: third_party/WebKit/Source/core/loader/resource/ImageResource.cpp
diff --git a/third_party/WebKit/Source/core/loader/resource/ImageResource.cpp b/third_party/WebKit/Source/core/loader/resource/ImageResource.cpp
index c91542567a841ce12ec16894141b4a8d9b1fb2b8..294416899427b764c5ca8873aeeae5101279063f 100644
--- a/third_party/WebKit/Source/core/loader/resource/ImageResource.cpp
+++ b/third_party/WebKit/Source/core/loader/resource/ImageResource.cpp
@@ -436,6 +436,7 @@ void ImageResource::responseReceived(
 bool ImageResource::shouldShowPlaceholder() const {
   switch (m_placeholderOption) {
     case PlaceholderOption::ShowAndReloadPlaceholderAlways:
+    case PlaceholderOption::ShowAndDoNotReloadPlaceholder:
       return true;
     case PlaceholderOption::ReloadPlaceholderOnDecodeError:
     case PlaceholderOption::DoNotReloadPlaceholder:
@@ -451,6 +452,7 @@ bool ImageResource::shouldReloadBrokenPlaceholder() const {
       return errorOccurred();
     case PlaceholderOption::ReloadPlaceholderOnDecodeError:
       return getStatus() == ResourceStatus::DecodeError;
+    case PlaceholderOption::ShowAndDoNotReloadPlaceholder:
     case PlaceholderOption::DoNotReloadPlaceholder:
       return false;
   }
@@ -488,11 +490,19 @@ void ImageResource::reloadIfLoFiOrPlaceholderImage(
 
   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();