[LargeIconService] Allow overriding request URL by a field trial param

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/feature_list.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/field_trial_params.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 "components/image_fetcher/core/request_metadata.h"
 #include "skia/ext/image_operations.h"
 #include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/geometry/size.h"
 #include "url/url_canon.h"
 
 namespace favicon {
 namespace {
 
+// This feature is only used for accessing field trial parameters, not for
+// switching on/off the code.
+const base::Feature kLargeIconServiceFetchingFeature{
+    "LargeIconServiceFetching", base::FEATURE_ENABLED_BY_DEFAULT};
+
 const char kGoogleServerV2RequestFormat[] =
     "https://t0.gstatic.com/faviconV2?"
-    "client=chrome&drop_404_icon=true&size=%d&min_size=%d&max_size=%d&"
+    "client=chrome&drop_404_icon=true&size=32&min_size=%d&max_size=64&"
     "fallback_opts=TYPE,SIZE,URL&url=%s";
-const int kGoogleServerV2MaxSizeInPixel = 128;
-const int kGoogleServerV2DesiredSizeInPixel = 64;
+const char kGoogleServerV2RequestFormatParam[] = "request_format";
 
 GURL TrimPageUrlForGoogleServer(const GURL& page_url) {
   if (!page_url.SchemeIsHTTPOrHTTPS() || page_url.HostIsIPAddress())
     return GURL();
 
   url::Replacements<char> replacements;
   replacements.ClearUsername();
   replacements.ClearPassword();
   replacements.ClearQuery();
   replacements.ClearRef();
   return page_url.ReplaceComponents(replacements);
 }
 
 GURL GetRequestUrlForGoogleServerV2(const GURL& page_url,
                                     int min_source_size_in_pixel) {
+  std::string url_format = base::GetFieldTrialParamValueByFeature(
+      kLargeIconServiceFetchingFeature, kGoogleServerV2RequestFormatParam);
+
   return GURL(base::StringPrintf(
-      kGoogleServerV2RequestFormat, kGoogleServerV2DesiredSizeInPixel,
-      min_source_size_in_pixel, kGoogleServerV2MaxSizeInPixel,
-      page_url.spec().c_str()));
+      url_format.empty() ? kGoogleServerV2RequestFormat : url_format.c_str(),
+      min_source_size_in_pixel, page_url.spec().c_str()));
 }
 
 bool IsDbResultAdequate(const favicon_base::FaviconRawBitmapResult& db_result,
                         int min_source_size) {
   return db_result.is_valid() &&
          db_result.pixel_size.width() == db_result.pixel_size.height() &&
          db_result.pixel_size.width() >= min_source_size;
 }
 
 // Wraps the PNG data in |db_result| in a gfx::Image. If |desired_size| is not
@@ skipping 245 matching lines @@
         int min_source_size_in_pixel,
         const base::Callback<void(bool success)>& callback) {
   DCHECK_LE(0, min_source_size_in_pixel);
 
   const GURL trimmed_page_url = TrimPageUrlForGoogleServer(page_url);
   const GURL server_request_url = GetRequestUrlForGoogleServerV2(
       trimmed_page_url, min_source_size_in_pixel);
 
   // Do not download if the URL is invalid after trimming, or there is a
   // previous cache miss recorded for |server_request_url|.
-  if (!trimmed_page_url.is_valid() || !image_fetcher_ ||
+  if (!server_request_url.is_valid() || !trimmed_page_url.is_valid() ||
+      !image_fetcher_ ||
       favicon_service_->WasUnableToDownloadFavicon(server_request_url)) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
                                                   base::Bind(callback, false));
     return;
   }
 
   image_fetcher_->SetDataUseServiceName(
       data_use_measurement::DataUseUserData::LARGE_ICON_SERVICE);
   image_fetcher_->StartOrQueueNetworkRequest(
       server_request_url.spec(), server_request_url,
@@ skipping 19 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