[LargeIconService] Report size of the downloaded favicon to UMA

components/favicon/core/large_icon_service.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/favicon/core/large_icon_service.h"
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #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"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/data_use_measurement/core/data_use_user_data.h"
 #include "components/favicon/core/favicon_service.h"
 #include "components/favicon_base/fallback_icon_style.h"
 #include "components/favicon_base/favicon_types.h"
 #include "components/favicon_base/favicon_util.h"
 #include "skia/ext/image_operations.h"
@@ skipping 196 matching lines @@
     const GURL& page_url,
     const base::Callback<void(bool success)>& callback,
     const std::string& icon_url,
     const gfx::Image& image,
     const image_fetcher::RequestMetadata& metadata) {
   if (image.IsEmpty()) {
     DLOG(WARNING) << "large icon server fetch empty " << icon_url;
     favicon_service->UnableToDownloadFavicon(GURL(icon_url));
     base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
                                                   base::Bind(callback, false));
+    UMA_HISTOGRAM_COUNTS_1000("Favicons.LargeIconService.DownloadedSize", 0);
     return;
   }
 
+  UMA_HISTOGRAM_COUNTS_1000("Favicons.LargeIconService.DownloadedSize",
+                            image.Width());

[Ilya Sherman, 2017/04/07 19:26:47]

nit: Histogram macros expand to a fair bit of code, so please help the compiler
be more efficient by providing a small wrapper function for emitting to this
histogram.

[jkrcal, 2017/04/11 19:25:37]

Done.

+
   // TODO(crbug.com/699542): Extract the original icon url from the response
   // headers if available and use it instead of |icon_url|. Possibly the type
   // too, because using TOUCH_ICON is a hacky way that allows us to not
   // interfere with sync.
 
   // Write fetched icons to FaviconService's cache, but only if no icon was
   // available (clients are encouraged to do this in advance, but meanwhile
   // something else could've been written). By marking the icons initially
   // expired (out-of-date), they will be refetched when we visit the original
   // page any time in the future.
@@ skipping 89 matching lines @@
   // TODO(beaudoin): For now this is just a wrapper around
   //   GetLargestRawFaviconForPageURL. Add the logic required to select the best
   //   possible large icon. Also add logic to fetch-on-demand when the URL of
   //   a large icon is known but its bitmap is not available.
   return favicon_service_->GetLargestRawFaviconForPageURL(
       page_url, large_icon_types_, min_source_size_in_pixel,
       base::Bind(&LargeIconWorker::OnIconLookupComplete, worker), tracker);
 }
 
 }  // namespace favicon