[Adaptation] Remove processing_in_progress_ from ResourceAdaptationProcessor

This flag was used to protect an AdaptationListener from adapting again,
but since AdaptationListener was removed this guard is no longer needed.

Bug: webrtc:11834
Change-Id: If79e960f57aaf56ce2849329ff6737414fc60e9a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/181068
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Evan Shrubsole <eshr@google.com>
Cr-Commit-Position: refs/heads/master@{#31905}
diff --git a/call/adaptation/resource_adaptation_processor.cc b/call/adaptation/resource_adaptation_processor.cc
index b3095ed..b988479 100644
--- a/call/adaptation/resource_adaptation_processor.cc
+++ b/call/adaptation/resource_adaptation_processor.cc
@@ -78,8 +78,7 @@
       resources_(),
       stream_adapter_(stream_adapter),
       last_reported_source_restrictions_(),
-      previous_mitigation_results_(),
-      processing_in_progress_(false) {
+      previous_mitigation_results_() {
   RTC_DCHECK(stream_adapter_);
 }
 
@@ -244,12 +243,9 @@
 ResourceAdaptationProcessor::OnResourceUnderuse(
     rtc::scoped_refptr<Resource> reason_resource) {
   RTC_DCHECK_RUN_ON(resource_adaptation_queue_);
-  RTC_DCHECK(!processing_in_progress_);
-  processing_in_progress_ = true;
   // How can this stream be adapted up?
   Adaptation adaptation = stream_adapter_->GetAdaptationUp(reason_resource);
   if (adaptation.status() != Adaptation::Status::kValid) {
-    processing_in_progress_ = false;
     rtc::StringBuilder message;
     message << "Not adapting up because VideoStreamAdapter returned "
             << Adaptation::StatusToString(adaptation.status());
@@ -271,7 +267,6 @@
     // adaptation.
     if (absl::c_find(most_limited_resources, reason_resource) ==
         most_limited_resources.end()) {
-      processing_in_progress_ = false;
       rtc::StringBuilder message;
       message << "Resource \"" << reason_resource->Name()
               << "\" was not the most limited resource.";
@@ -284,7 +279,6 @@
       // before the adaptation is applied.
       UpdateResourceLimitations(reason_resource, adaptation.restrictions(),
                                 adaptation.counters());
-      processing_in_progress_ = false;
       rtc::StringBuilder message;
       message << "Resource \"" << reason_resource->Name()
               << "\" was not the only most limited resource.";
@@ -294,7 +288,6 @@
   }
   // Apply adaptation.
   stream_adapter_->ApplyAdaptation(adaptation, reason_resource);
-  processing_in_progress_ = false;
   rtc::StringBuilder message;
   message << "Adapted up successfully. Unfiltered adaptations: "
           << stream_adapter_->adaptation_counters().ToString();
@@ -306,15 +299,12 @@
 ResourceAdaptationProcessor::OnResourceOveruse(
     rtc::scoped_refptr<Resource> reason_resource) {
   RTC_DCHECK_RUN_ON(resource_adaptation_queue_);
-  RTC_DCHECK(!processing_in_progress_);
-  processing_in_progress_ = true;
   // How can this stream be adapted up?
   Adaptation adaptation = stream_adapter_->GetAdaptationDown();
   if (adaptation.min_pixel_limit_reached()) {
     encoder_stats_observer_->OnMinPixelLimitReached();
   }
   if (adaptation.status() != Adaptation::Status::kValid) {
-    processing_in_progress_ = false;
     rtc::StringBuilder message;
     message << "Not adapting down because VideoStreamAdapter returned "
             << Adaptation::StatusToString(adaptation.status());
@@ -325,7 +315,6 @@
   UpdateResourceLimitations(reason_resource, adaptation.restrictions(),
                             adaptation.counters());
   stream_adapter_->ApplyAdaptation(adaptation, reason_resource);
-  processing_in_progress_ = false;
   rtc::StringBuilder message;
   message << "Adapted down successfully. Unfiltered adaptations: "
           << stream_adapter_->adaptation_counters().ToString();
diff --git a/call/adaptation/resource_adaptation_processor.h b/call/adaptation/resource_adaptation_processor.h
index 7ba871e..9e5dd6c 100644
--- a/call/adaptation/resource_adaptation_processor.h
+++ b/call/adaptation/resource_adaptation_processor.h
@@ -168,18 +168,6 @@
   // successful adaptation. Used to avoid RTC_LOG spam.
   std::map<Resource*, MitigationResult> previous_mitigation_results_
       RTC_GUARDED_BY(resource_adaptation_queue_);
-  // Prevents recursion.
-  //
-  // This is used to prevent triggering resource adaptation in the process of
-  // already handling resouce adaptation, since that could cause the same states
-  // to be modified in unexpected ways. Example:
-  //
-  // Resource::OnResourceUsageStateMeasured() ->
-  // ResourceAdaptationProcessor::OnResourceOveruse() ->
-  // Resource::OnAdaptationApplied() ->
-  // Resource::OnResourceUsageStateMeasured() ->
-  // ResourceAdaptationProcessor::OnResourceOveruse() // Boom, not allowed.
-  bool processing_in_progress_ RTC_GUARDED_BY(resource_adaptation_queue_);
 };
 
 }  // namespace webrtc