[Favicon] Add new fallback icon rendering flow.

chrome/browser/ui/webui/ntp/most_visited_handler.cc

Index: chrome/browser/ui/webui/ntp/most_visited_handler.cc
diff --git a/chrome/browser/ui/webui/ntp/most_visited_handler.cc b/chrome/browser/ui/webui/ntp/most_visited_handler.cc
index 704380e324a05f29910a7d72b3a5f9705e57b7c2..6a07d7aca67d75a1c0c4b6194aea0db0ea6401c8 100644
--- a/chrome/browser/ui/webui/ntp/most_visited_handler.cc
+++ b/chrome/browser/ui/webui/ntp/most_visited_handler.cc
@@ -28,6 +28,7 @@
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/browser/ui/tabs/tab_strip_model_utils.h"
+#include "chrome/browser/ui/webui/fallback_icon_source.h"
 #include "chrome/browser/ui/webui/favicon_source.h"
 #include "chrome/browser/ui/webui/ntp/new_tab_ui.h"
 #include "chrome/browser/ui/webui/ntp/ntp_stats.h"
@@ -79,6 +80,9 @@ void MostVisitedHandler::RegisterMessages() {
   // Set up our sources for top-sites data.
   content::URLDataSource::Add(profile, new ThumbnailListSource(profile));
 
+  // Register chrome://fallback-icon as a data source for fallback icons.
+  content::URLDataSource::Add(profile, new FallbackIconSource());

[pkotwicz, 2015/01/21 19:44:15]

I think that this is the only place (not sure about InstantService) that you
need to register FallbackIconSource. (For now, it will only be possible to get
fallback icons from Web UI via the NTP)

[huangs, 2015/01/22 01:13:27]

Acknowledged.  I want to be able to type in the chrome://fallback-icon URL and
see it working though -- for testing.

+
   // Register chrome://favicon as a data source for favicons.
   content::URLDataSource::Add(
       profile, new FaviconSource(profile, FaviconSource::FAVICON));