Avoid retaining a reference to ActivityIconLoader in its OnIconReady()

components/arc/intent_helper/activity_icon_loader.cc

 // Copyright 2016 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/arc/intent_helper/activity_icon_loader.h"
 
 #include <string.h>
 
 #include <tuple>
 #include <utility>
@@ skipping 59 matching lines @@
   return std::tie(package_name, activity_name) <
          std::tie(other.package_name, other.activity_name);
 }
 
 ActivityIconLoader::ActivityIconLoader()
     : scale_factor_(GetSupportedScaleFactor()) {}
 
 ActivityIconLoader::~ActivityIconLoader() {}
 
 void ActivityIconLoader::InvalidateIcons(const std::string& package_name) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   for (auto it = cached_icons_.begin(); it != cached_icons_.end();) {
     if (it->first.package_name == package_name)
       it = cached_icons_.erase(it);
     else
       ++it;
   }
 }
 
 ActivityIconLoader::GetResult ActivityIconLoader::GetActivityIcons(
     const std::vector<ActivityName>& activities,
     const OnIconsReadyCallback& cb) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   std::unique_ptr<ActivityToIconsMap> result(new ActivityToIconsMap);
   std::vector<mojom::ActivityNamePtr> activities_to_fetch;
 
   for (const auto& activity : activities) {
     const auto& it = cached_icons_.find(activity);
     if (it == cached_icons_.end()) {
       mojom::ActivityNamePtr name(mojom::ActivityName::New());
       name->package_name = activity.package_name;
       name->activity_name = activity.activity_name;
       activities_to_fetch.push_back(std::move(name));
@@ skipping 52 matching lines @@
     case GetResult::FAILED_ARC_NOT_SUPPORTED:
       break;
   }
   return true;
 }
 
 void ActivityIconLoader::OnIconsReady(
     std::unique_ptr<ActivityToIconsMap> cached_result,
     const OnIconsReadyCallback& cb,
     std::vector<mojom::ActivityIconPtr> icons) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   ArcServiceManager* manager = ArcServiceManager::Get();
   base::PostTaskAndReplyWithResult(
       manager->blocking_task_runner().get(), FROM_HERE,
-      base::Bind(&ActivityIconLoader::ResizeAndEncodeIcons, this,
+      base::Bind(&ActivityIconLoader::ResizeAndEncodeIcons,
                  base::Passed(&icons)),
       base::Bind(&ActivityIconLoader::OnIconsResized, this,
                  base::Passed(&cached_result), cb));
 }
 
+// static
 std::unique_ptr<ActivityIconLoader::ActivityToIconsMap>
 ActivityIconLoader::ResizeAndEncodeIcons(
     std::vector<mojom::ActivityIconPtr> icons) {
-  // Runs only on the blocking pool.
-  DCHECK(thread_checker_.CalledOnValidThread());
   std::unique_ptr<ActivityToIconsMap> result(new ActivityToIconsMap);
 
   for (size_t i = 0; i < icons.size(); ++i) {
     static const size_t kBytesPerPixel = 4;
     const mojom::ActivityIconPtr& icon = icons.at(i);
     if (icon->width > kMaxIconSizeInPx || icon->height > kMaxIconSizeInPx ||
         icon->width == 0 || icon->height == 0 ||
         icon->icon.size() != (icon->width * icon->height * kBytesPerPixel)) {
       continue;
     }
@@ skipping 35 matching lines @@
         Icons(icon16, icon20, dataurl)));
   }
 
   return result;
 }
 
 void ActivityIconLoader::OnIconsResized(
     std::unique_ptr<ActivityToIconsMap> cached_result,
     const OnIconsReadyCallback& cb,
     std::unique_ptr<ActivityToIconsMap> result) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   // Update |cached_icons_|.
   for (const auto& kv : *result) {
     cached_icons_.erase(kv.first);
     cached_icons_.insert(std::make_pair(kv.first, kv.second));
   }
 
   // Merge the results that were obtained from cache before doing IPC.
   result->insert(cached_result->begin(), cached_result->end());
   cb.Run(std::move(result));
 }
 
 }  // namespace arc