Add timeout eviction for bfcache in ResponseBodyLoader, URLLoaderClientImpl

Ensures we won't keep a connection too long when deferred for bfcache.
The timeout is determined by the "max_time_to_live" param of
kLoadingTasksUnfreezable, defaulting to 15 seconds.

Bug: 1137682
Change-Id: I66cb229285f40ef12a69734975ac77c820a02082
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2569020
Commit-Queue: Rakina Zata Amni <rakina@chromium.org>
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833609}

third_party/blink/renderer/platform/loader/fetch/resource_fetcher.cc

@@ -92,6 +92,7 @@
 namespace blink {
 
 constexpr uint32_t ResourceFetcher::kKeepaliveInflightBytesQuota;
+constexpr int kDefaultTimeToLiveWhileInBackForwardCacheInSeconds = 15;
 
 namespace {
 
@@ -618,6 +619,11 @@ ResourceFetcher::ResourceFetcher(const ResourceFetcherInit& init)
   InstanceCounters::IncrementCounter(InstanceCounters::kResourceFetcherCounter);
   if (IsMainThread())
     MainThreadFetchersSet().insert(this);
+
+  back_forward_cache_timeout_ =
+      base::TimeDelta::FromSeconds(base::GetFieldTrialParamByFeatureAsInt(
+          blink::features::kLoadingTasksUnfreezable, "max_time_to_live",
+          kDefaultTimeToLiveWhileInBackForwardCacheInSeconds));
 }
 
 ResourceFetcher::~ResourceFetcher() {
@@ -2094,6 +2100,36 @@ void ResourceFetcher::SetDefersLoading(WebURLLoader::DeferType defers) {
     loader->SetDefersLoading(defers);
   for (const auto& loader : loaders_)
     loader->SetDefersLoading(defers);
+  if (defers == WebURLLoader::DeferType::kDeferredWithBackForwardCache &&
+      !back_forward_cache_eviction_timer_.IsRunning()) {
+    back_forward_cache_eviction_timer_.SetTaskRunner(unfreezable_task_runner_);
+    back_forward_cache_eviction_timer_.Start(
+        FROM_HERE, back_forward_cache_timeout_,
+        base::BindOnce(&ResourceFetcher::OnBackForwardCacheEvictionTimerFired,
+                       weak_ptr_factory_.GetWeakPtr()));
+  } else if (defers != WebURLLoader::DeferType::kDeferredWithBackForwardCache) {
+    // The page associated with this ResourceFetcher is no longer in the
+    // back-forward cache, so stop the back-forward cache eviction timer if it's
+    // currently running.
+    if (back_forward_cache_eviction_timer_.IsRunning())
+      back_forward_cache_eviction_timer_.Stop();
+  }
+}
+
+void ResourceFetcher::OnBackForwardCacheEvictionTimerFired() {
+  // If all the loaders are keepalive, we don't need to evict.
+  bool all_loaders_are_keepalive = true;
+  for (const auto& loader : loaders_) {
+    all_loaders_are_keepalive &= loader->ShouldBeKeptAliveWhenDetached();
+  }
+  for (const auto& loader : non_blocking_loaders_) {
+    all_loaders_are_keepalive &= loader->ShouldBeKeptAliveWhenDetached();
+  }
+  if (all_loaders_are_keepalive)
+    return;
+
+  StopFetching();
+  EvictFromBackForwardCache();
 }
 
 void ResourceFetcher::UpdateAllImageResourcePriorities() {

third_party/blink/renderer/platform/loader/fetch/resource_fetcher.h

@@ -415,6 +415,8 @@ class PLATFORM_EXPORT ResourceFetcher
 
   void WarnUnusedPreloads();
 
+  void OnBackForwardCacheEvictionTimerFired();
+
   Member<DetachableResourceFetcherProperties> properties_;
   Member<ResourceLoadObserver> resource_load_observer_;
   Member<FetchContext> context_;
@@ -468,6 +470,9 @@ class PLATFORM_EXPORT ResourceFetcher
 
   HeapHashSet<Member<SubresourceWebBundle>> subresource_web_bundles_;
 
+  base::OneShotTimer back_forward_cache_eviction_timer_;
+  base::TimeDelta back_forward_cache_timeout_;
+
   // This is not in the bit field below because we want to use AutoReset.
   bool is_in_request_resource_ = false;
 
@@ -482,6 +487,9 @@ class PLATFORM_EXPORT ResourceFetcher
 
   static constexpr uint32_t kKeepaliveInflightBytesQuota = 64 * 1024;
 
+  // NOTE: This must be the last member.
+  base::WeakPtrFactory<ResourceFetcher> weak_ptr_factory_{this};
+
   DISALLOW_COPY_AND_ASSIGN(ResourceFetcher);
 };