[LargeIconService] Report size of the downloaded favicon to UMA

components/favicon/core/large_icon_service.cc

Index: components/favicon/core/large_icon_service.cc
diff --git a/components/favicon/core/large_icon_service.cc b/components/favicon/core/large_icon_service.cc
index 5817bfcfd582732158a922313c18e07c2f659297..c202c244ff784f4bb1634ee2b80da8a9e69e19b7 100644
--- a/components/favicon/core/large_icon_service.cc
+++ b/components/favicon/core/large_icon_service.cc
@@ -12,6 +12,7 @@
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/stringprintf.h"
 #include "base/task_runner.h"
 #include "base/threading/sequenced_worker_pool.h"
@@ -217,6 +218,10 @@ void LargeIconWorker::OnIconProcessingComplete() {
       favicon_base::LargeIconImageResult(fallback_icon_style_.release()));
 }
 
+void ReportDownloadedSize(int size) {
+  UMA_HISTOGRAM_COUNTS_1000("Favicons.LargeIconService.DownloadedSize", size);
+}
+
 void OnFetchIconFromGoogleServerComplete(
     FaviconService* favicon_service,
     const GURL& page_url,
@@ -229,9 +234,12 @@ void OnFetchIconFromGoogleServerComplete(
     favicon_service->UnableToDownloadFavicon(GURL(server_request_url));
     base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
                                                   base::Bind(callback, false));
+    ReportDownloadedSize(0);
     return;
   }
 
+  ReportDownloadedSize(image.Width());
+
   // If given, use the original favicon URL from Content-Location http header.
   // Otherwise, use the request URL as fallback.
   std::string original_icon_url = metadata.content_location_header;