Reduce jank from favicon downscaling.

components/history/core/browser/history_backend.cc

 // Copyright (c) 2012 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/history/core/browser/history_backend.h"
 
 #include <algorithm>
 #include <functional>
 #include <list>
 #include <map>
 #include <memory>
 #include <set>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/files/file_enumerator.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/rand_util.h"
 #include "base/sequenced_task_runner.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
+#include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
+#include "components/favicon_base/favicon_util.h"
 #include "components/favicon_base/select_favicon_frames.h"
 #include "components/history/core/browser/download_constants.h"
 #include "components/history/core/browser/download_row.h"
 #include "components/history/core/browser/history_backend_client.h"
 #include "components/history/core/browser/history_backend_observer.h"
 #include "components/history/core/browser/history_constants.h"
 #include "components/history/core/browser/history_database.h"
 #include "components/history/core/browser/history_database_params.h"
 #include "components/history/core/browser/history_db_task.h"
 #include "components/history/core/browser/in_memory_history_backend.h"
@@ skipping 1496 matching lines @@
 
   LOCAL_HISTOGRAM_TIMES("History.GetLargestFaviconForURL",
                         TimeTicks::Now() - beginning_time);
 }
 
 void HistoryBackend::GetFaviconsForURL(
     const GURL& page_url,
     int icon_types,
     const std::vector<int>& desired_sizes,
     std::vector<favicon_base::FaviconRawBitmapResult>* bitmap_results) {
+  TRACE_EVENT0("browser", "HistoryBackend::GetFaviconsForURL");
   DCHECK(bitmap_results);
   GetFaviconsFromDB(page_url, icon_types, desired_sizes, bitmap_results);
+
+  if (desired_sizes.size() == 1)
+    bitmap_results->assign(1, favicon_base::ResizeFaviconBitmapResult(
+                                  *bitmap_results, desired_sizes[0]));
 }
 
 void HistoryBackend::GetFaviconForID(
     favicon_base::FaviconID favicon_id,
     int desired_size,
     std::vector<favicon_base::FaviconRawBitmapResult>* bitmap_results) {
+  TRACE_EVENT0("browser", "HistoryBackend::GetFaviconForID");
   std::vector<favicon_base::FaviconID> favicon_ids;
   favicon_ids.push_back(favicon_id);
   std::vector<int> desired_sizes;
   desired_sizes.push_back(desired_size);
 
   // Get results from DB.
   GetFaviconBitmapResultsForBestMatch(favicon_ids, desired_sizes,
                                       bitmap_results);
+
+  bitmap_results->assign(1, favicon_base::ResizeFaviconBitmapResult(
+                                *bitmap_results, desired_size));
 }
 
 void HistoryBackend::UpdateFaviconMappingsAndFetch(
     const GURL& page_url,
     const std::vector<GURL>& icon_urls,
     int icon_types,
     const std::vector<int>& desired_sizes,
     std::vector<favicon_base::FaviconRawBitmapResult>* bitmap_results) {
   UpdateFaviconMappingsAndFetchImpl(&page_url, icon_urls, icon_types,
                                     desired_sizes, bitmap_results);
@@ skipping 1059 matching lines @@
   // transaction is currently open.
   db_->CommitTransaction();
   db_->Vacuum();
   db_->BeginTransaction();
   db_->GetStartDate(&first_recorded_time_);
 
   return true;
 }
 
 }  // namespace history