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 1434eb5ec11d59fde4792447bb79c712f4ed7163..de9d58da023a27ca6c3060c5b3639a85c417b8fb 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;
@@ -228,7 +233,9 @@ 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_.reset();
   candidates_.clear();
   notification_icon_url_ = GURL();
   notification_icon_type_ = favicon_base::INVALID_ICON;
@@ -316,10 +323,93 @@ 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 base::Optional<GURL>& manifest_url) {
+  DCHECK_EQ(page_url, url_);
   if (page_url != url_)
     return;
 
+  if (base::FeatureList::IsEnabled(kFaviconsFromWebManifest)) {
+    // |candidates| or |manifest_url| could have been modified via Javascript.
+    if (manifest_url_ && manifest_url_ == manifest_url)
+      return;
+
+    manifest_url_ = manifest_url;
+  }
+
+  non_manifest_original_candidates_ = candidates;
+
+  // 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_ && service_->WasUnableToDownloadFavicon(*manifest_url_)) {
+    DVLOG(1) << "Skip failed Manifest: " << *manifest_url_;
+    manifest_url_.reset();
+  }
+
+  if (manifest_url_) {
+    cancelable_task_tracker_for_candidates_.TryCancelAll();
+    // See if there is a cached favicon for the manifest.
+    GetFaviconAndUpdateMappingsUnlessIncognito(
+        /*icon_url=*/*manifest_url_, favicon_base::FAVICON,
+        base::Bind(&FaviconHandler::OnFaviconDataForManifestFromFaviconService,
+                   base::Unretained(this)));
+  } else {
+    // If no manifest available, proceed with the regular candidates only.
+    OnGotFinalIconURLCandidates(candidates);
+  }
+}
+
+void FaviconHandler::OnFaviconDataForManifestFromFaviconService(
+    const std::vector<favicon_base::FaviconRawBitmapResult>&
+        favicon_bitmap_results) {
+  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) {
+    // 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(
+    int status_code,
+    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();
+
+  // Don't blacklist 5xx errors.
+  if (status_code / 100 != 5)
+    service_->UnableToDownloadFavicon(*manifest_url_);
+
+  manifest_url_.reset();
+  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_);
@@ -438,9 +528,10 @@ 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. Note that
+      // manifest URLs override icon URLs if available.
+      SetFavicon(manifest_url_.value_or(best_favicon_.candidate.icon_url),
+                 best_favicon_.image, best_favicon_.candidate.icon_type);
     }
     // Clear download related state.
     current_candidate_index_ = candidates_.size();
@@ -458,6 +549,7 @@ 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();
 }
@@ -482,15 +574,20 @@ void FaviconHandler::OnFaviconDataForInitialURLFromFaviconService(
   redownload_icons_ = initial_history_result_expired_or_incomplete_ &&
                       !favicon_bitmap_results.empty();
 
-  if (has_valid_result && (!current_candidate() ||
-                           DoUrlsAndIconsMatch(current_candidate()->icon_url,
-                                               current_candidate()->icon_type,
-                                               favicon_bitmap_results))) {
-    // The db knows the favicon (although it may be out of date) and the entry
-    // doesn't have an icon. Set the favicon now, and if the favicon turns out
-    // to be expired (or the wrong url) we'll fetch later on. This way the
-    // user doesn't see a flash of the default favicon.
-    NotifyFaviconUpdated(favicon_bitmap_results);
+  if (has_valid_result) {
+    if (!current_candidate() ||
+        DoUrlsAndIconsMatch(current_candidate()->icon_url,
+                            current_candidate()->icon_type,
+                            favicon_bitmap_results) ||
+        (manifest_url_ &&
+         DoUrlsAndIconsMatch(*manifest_url_, favicon_base::FAVICON,
+                             favicon_bitmap_results))) {
+      // The db knows the favicon (although it may be out of date) and the entry
+      // doesn't have an icon. Set the favicon now, and if the favicon turns out
+      // to be expired (or the wrong url) we'll fetch later on. This way the
+      // user doesn't see a flash of the default favicon.
+      NotifyFaviconUpdated(favicon_bitmap_results);
+    }
   }
 
   if (current_candidate())
@@ -498,32 +595,40 @@ 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 anyway,
+  // and this lookup has happened earlier.
+  if (redownload_icons_ || manifest_url_) {
     // 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_);
   }
 }