Add support to process favicons from Web Manifests

components/favicon/core/favicon_handler.cc

Index: components/favicon/core/favicon_handler.cc
diff --git a/components/favicon/core/favicon_handler.cc b/components/favicon/core/favicon_handler.cc
index f811c350376f517a6888ab7222b2e98e9929e5cf..8f8622d7e79db019d6987d195f6867b0e84605b8 100644
--- a/components/favicon/core/favicon_handler.cc
+++ b/components/favicon/core/favicon_handler.cc
@@ -11,6 +11,7 @@
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
+#include "base/feature_list.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/metrics/histogram_macros.h"
 #include "build/build_config.h"
@@ -23,6 +24,10 @@
 #include "ui/gfx/image/image_util.h"
 
 namespace favicon {
+
+const base::Feature kFaviconsFromWebManifest{"FaviconsFromWebManifest",
+                                             base::FEATURE_DISABLED_BY_DEFAULT};
+
 namespace {
 
 const int kNonTouchLargestIconSize = 192;
@@ -141,6 +146,11 @@ std::vector<int> GetDesiredPixelSizes(
   return std::vector<int>();
 }
 
+bool FaviconURLEquals(const FaviconURL& lhs, const FaviconURL& rhs) {
+  return lhs.icon_url == rhs.icon_url && lhs.icon_type == rhs.icon_type &&
+         lhs.icon_sizes == rhs.icon_sizes;
+}
+
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -209,7 +219,10 @@ void FaviconHandler::FetchFavicon(const GURL& url) {
   initial_history_result_expired_or_incomplete_ = false;
   redownload_icons_ = false;
   got_favicon_from_history_ = false;
+  manifest_download_request_.Cancel();
   image_download_request_.Cancel();
+  manifest_url_ = GURL();
+  non_manifest_original_candidates_.clear();
   candidates_.clear();
   notification_icon_url_ = GURL();
   notification_icon_type_ = favicon_base::INVALID_ICON;
@@ -297,10 +310,111 @@ void FaviconHandler::NotifyFaviconUpdated(const GURL& icon_url,
 
 void FaviconHandler::OnUpdateCandidates(
     const GURL& page_url,
-    const std::vector<FaviconURL>& candidates) {
+    const std::vector<FaviconURL>& candidates,
+    const GURL& manifest_url) {
   if (page_url != url_)
     return;
 
+  bool manifests_feature_enabled =
+      base::FeatureList::IsEnabled(kFaviconsFromWebManifest);
+
+  // |candidates| or |manifest_url| could have been modified via Javascript. If
+  // neither changed, ignore the call.
+  if ((!manifests_feature_enabled || manifest_url_ == manifest_url) &&
+      non_manifest_original_candidates_.size() == candidates.size() &&
+      std::equal(candidates.begin(), candidates.end(),
+                 non_manifest_original_candidates_.begin(),
+                 &FaviconURLEquals)) {
+    return;
+  }
+
+  non_manifest_original_candidates_ = candidates;
+  cancelable_task_tracker_for_candidates_.TryCancelAll();
+  manifest_download_request_.Cancel();
+  image_download_request_.Cancel();
+  num_image_download_requests_ = 0;
+  current_candidate_index_ = 0u;
+  best_favicon_ = DownloadedFavicon();
+
+  if (manifests_feature_enabled)
+    manifest_url_ = manifest_url;
+
+  // Check if the manifest was previously blacklisted (e.g. returned a 404) and
+  // ignore the manifest URL if that's the case.
+  if (!manifest_url_.is_empty() &&
+      service_->WasUnableToDownloadFavicon(manifest_url_)) {
+    DVLOG(1) << "Skip failed Manifest: " << manifest_url;
+    manifest_url_ = GURL();
+  }
+
+  // If no manifest available, proceed with the regular candidates only.
+  if (manifest_url_.is_empty()) {
+    OnGotFinalIconURLCandidates(candidates);
+    return;
+  }
+
+  // See if there is a cached favicon for the manifest. This will update the DB
+  // mappings only if the manifest URL is cached.
+  GetFaviconAndUpdateMappingsUnlessIncognito(
+      /*icon_url=*/manifest_url_, favicon_base::FAVICON,
+      base::Bind(&FaviconHandler::OnFaviconDataForManifestFromFaviconService,
+                 base::Unretained(this)));
+}
+
+void FaviconHandler::OnFaviconDataForManifestFromFaviconService(
+    const std::vector<favicon_base::FaviconRawBitmapResult>&
+        favicon_bitmap_results) {
+  // The database lookup for the page URL is guaranteed to be completed because
+  // the HistoryBackend uses a SequencedTaskRunner, and we also know that
+  // FetchFavicon() was called before OnUpdateCandidates().
+  DCHECK(got_favicon_from_history_);
+
+  bool has_valid_result = HasValidResult(favicon_bitmap_results);
+  bool has_expired_or_incomplete_result =
+      !has_valid_result || HasExpiredOrIncompleteResult(preferred_icon_size(),
+                                                        favicon_bitmap_results);
+
+  if (has_valid_result && (notification_icon_url_ != manifest_url_ ||
+                           notification_icon_type_ != favicon_base::FAVICON)) {
+    // There is a valid favicon. Notify any observers. It is useful to notify
+    // the observers even if the favicon is expired or incomplete (incorrect
+    // size) because temporarily showing the user an expired favicon or
+    // streched favicon is preferable to showing the user the default favicon.
+    NotifyFaviconUpdated(favicon_bitmap_results);
+  }
+
+  if (has_expired_or_incomplete_result) {
+    manifest_download_request_.Reset(base::Bind(
+        &FaviconHandler::OnDidDownloadManifest, base::Unretained(this)));
+    delegate_->DownloadManifest(manifest_url_,
+                                manifest_download_request_.callback());
+  }
+}
+
+void FaviconHandler::OnDidDownloadManifest(
+    const std::vector<FaviconURL>& candidates) {
+  // Mark manifest download as finished.
+  manifest_download_request_.Cancel();
+
+  if (!candidates.empty()) {
+    OnGotFinalIconURLCandidates(candidates);
+    return;
+  }
+
+  // If either the downloading of the manifest failed, OR the manifest contains
+  // no icons, proceed with the list of icons listed in the HTML.
+  DVLOG(1) << "Could not fetch Manifest icons from " << manifest_url_
+           << ", falling back to inlined ones, which are "
+           << non_manifest_original_candidates_.size();
+
+  service_->UnableToDownloadFavicon(manifest_url_);
+  manifest_url_ = GURL();
+
+  OnGotFinalIconURLCandidates(non_manifest_original_candidates_);
+}
+
+void FaviconHandler::OnGotFinalIconURLCandidates(
+    const std::vector<FaviconURL>& candidates) {
   std::vector<FaviconCandidate> sorted_candidates;
   const std::vector<int> desired_pixel_sizes =
       GetDesiredPixelSizes(handler_type_);
@@ -314,18 +428,7 @@ void FaviconHandler::OnUpdateCandidates(
   std::stable_sort(sorted_candidates.begin(), sorted_candidates.end(),
                    &FaviconCandidate::CompareScore);
 
-  if (candidates_.size() == sorted_candidates.size() &&
-      std::equal(sorted_candidates.begin(), sorted_candidates.end(),
-                 candidates_.begin())) {
-    return;
-  }
-
-  cancelable_task_tracker_for_candidates_.TryCancelAll();
-  image_download_request_.Cancel();
   candidates_ = std::move(sorted_candidates);
-  num_image_download_requests_ = 0;
-  current_candidate_index_ = 0u;
-  best_favicon_ = DownloadedFavicon();
 
   // TODO(davemoore) Should clear on empty url. Currently we ignore it.
   // This appears to be what FF does as well.
@@ -419,9 +522,11 @@ void FaviconHandler::OnDidDownloadFavicon(
                                          num_image_download_requests_);
     // We have either found the ideal candidate or run out of candidates.
     if (best_favicon_.candidate.icon_type != favicon_base::INVALID_ICON) {
-      // No more icons to request, set the favicon from the candidate.
-      SetFavicon(best_favicon_.candidate.icon_url, best_favicon_.image,
-                 best_favicon_.candidate.icon_type);
+      // No more icons to request, set the favicon from the candidate. The
+      // manifest URL, if available, is used instead of the icon URL.
+      SetFavicon(manifest_url_.is_empty() ? best_favicon_.candidate.icon_url
+                                          : manifest_url_,
+                 best_favicon_.image, best_favicon_.candidate.icon_type);
     }
     // Clear download related state.
     current_candidate_index_ = candidates_.size();
@@ -439,6 +544,7 @@ const std::vector<GURL> FaviconHandler::GetIconURLs() const {
 
 bool FaviconHandler::HasPendingTasksForTest() {
   return !image_download_request_.IsCancelled() ||
+         !manifest_download_request_.IsCancelled() ||
          cancelable_task_tracker_for_page_url_.HasTrackedTasks() ||
          cancelable_task_tracker_for_candidates_.HasTrackedTasks();
 }
@@ -476,32 +582,40 @@ void FaviconHandler::OnFaviconDataForInitialURLFromFaviconService(
 }
 
 void FaviconHandler::DownloadCurrentCandidateOrAskFaviconService() {
-  GURL icon_url = current_candidate()->icon_url;
-  favicon_base::IconType icon_type = current_candidate()->icon_type;
-
-  if (redownload_icons_) {
+  const GURL icon_url = current_candidate()->icon_url;
+  const favicon_base::IconType icon_type = current_candidate()->icon_type;
+  // If the icons listed in a manifest are being processed, skip the cache
+  // lookup for |icon_url| since the manifest's URL is used for caching, not the
+  // icon URL, and this lookup has happened earlier.
+  if (redownload_icons_ || !manifest_url_.is_empty()) {
     // We have the mapping, but the favicon is out of date. Download it now.
     ScheduleImageDownload(icon_url, icon_type);
   } else {
-    // We don't know the favicon, but we may have previously downloaded the
-    // favicon for another page that shares the same favicon. Ask for the
-    // favicon given the favicon URL.
-    if (delegate_->IsOffTheRecord()) {
-      service_->GetFavicon(
-          icon_url, icon_type, preferred_icon_size(),
-          base::Bind(&FaviconHandler::OnFaviconData, base::Unretained(this)),
-          &cancelable_task_tracker_for_candidates_);
-    } else {
-      // Ask the history service for the icon. This does two things:
-      // 1. Attempts to fetch the favicon data from the database.
-      // 2. If the favicon exists in the database, this updates the database to
-      //    include the mapping between the page url and the favicon url.
-      // This is asynchronous. The history service will call back when done.
-      service_->UpdateFaviconMappingsAndFetch(
-          url_, icon_url, icon_type, preferred_icon_size(),
-          base::Bind(&FaviconHandler::OnFaviconData, base::Unretained(this)),
-          &cancelable_task_tracker_for_candidates_);
-    }
+    GetFaviconAndUpdateMappingsUnlessIncognito(
+        icon_url, icon_type,
+        base::Bind(&FaviconHandler::OnFaviconData, base::Unretained(this)));
+  }
+}
+
+void FaviconHandler::GetFaviconAndUpdateMappingsUnlessIncognito(
+    const GURL& icon_url,
+    favicon_base::IconType icon_type,
+    const favicon_base::FaviconResultsCallback& callback) {
+  // We don't know the favicon, but we may have previously downloaded the
+  // favicon for another page that shares the same favicon. Ask for the
+  // favicon given the favicon URL.
+  if (delegate_->IsOffTheRecord()) {
+    service_->GetFavicon(icon_url, icon_type, preferred_icon_size(), callback,
+                         &cancelable_task_tracker_for_candidates_);
+  } else {
+    // Ask the history service for the icon. This does two things:
+    // 1. Attempts to fetch the favicon data from the database.
+    // 2. If the favicon exists in the database, this updates the database to
+    //    include the mapping between the page url and the favicon url.
+    // This is asynchronous. The history service will call back when done.
+    service_->UpdateFaviconMappingsAndFetch(
+        url_, icon_url, icon_type, preferred_icon_size(), callback,
+        &cancelable_task_tracker_for_candidates_);
   }
 }