Report empty article as empty.

ios/chrome/browser/dom_distiller/distiller_viewer.cc

Index: ios/chrome/browser/dom_distiller/distiller_viewer.cc
diff --git a/ios/chrome/browser/dom_distiller/distiller_viewer.cc b/ios/chrome/browser/dom_distiller/distiller_viewer.cc
index a0bd94ab33f1f85bdf72d8163c7e06f943d71308..be17a3e82aaacc79b4ae7994c233460031a8b157 100644
--- a/ios/chrome/browser/dom_distiller/distiller_viewer.cc
+++ b/ios/chrome/browser/dom_distiller/distiller_viewer.cc
@@ -39,13 +39,19 @@ DistillerViewer::~DistillerViewer() {}
 void DistillerViewer::OnArticleReady(
     const dom_distiller::DistilledArticleProto* article_proto) {
   DomDistillerRequestViewBase::OnArticleReady(article_proto);

[wychen, 2016/12/22 07:58:19]

In DomDistillerRequestViewBase::OnArticleReady(), "No data found" is added to
js_buffer_.

[Olivier, 2016/12/22 10:54:59]

But IIUC, not the protobuf, correct?
Should I do my check before this call?

[wychen, 2016/12/22 11:05:12]

The protobuf should be intact, so no need to change. I was thinking about
calling it conditionally, but it does other things.

-  if (article_proto->pages_size() > 0) {
+  bool is_empty = true;
+  for (int i = 0; i < article_proto->pages_size(); i++) {

[wychen, 2016/12/22 10:19:33]

When the first distilled page is empty, even if the next page link is
discovered, the link would be disregarded. The logic is here:

https://cs.chromium.org/chromium/src/components/dom_distiller/core/distiller....

We did this because the distillability heuristic could still be wrong, and if
the page is not an article, stitching a paginated part would be moot.

Given this, we only need to check the first page here.

Your current implementation is defensive, and I'm fine with it.

[Olivier, 2016/12/22 10:54:59]

Done. This makes code simpler

+    if (article_proto->pages(i).html() != "") {

[wychen, 2016/12/22 10:19:33]

Using .empty() might be slightly better.

[Olivier, 2016/12/22 10:54:59]

Done.

+      is_empty = false;
+      break;
+    }
+  }
+  if (article_proto->pages_size() > 0 && !is_empty) {
     std::vector<ImageInfo> images;
     for (int i = 0; i < article_proto->pages(0).image_size(); i++) {
       auto image = article_proto->pages(0).image(i);
       images.push_back(ImageInfo{GURL(image.url()), image.data()});
     }
-
     const std::string html = viewer::GetUnsafeArticleTemplateHtml(
         url_.spec(), distilled_page_prefs_->GetTheme(),
         distilled_page_prefs_->GetFontFamily());