memory coordinator: Resume suspended renderer on NORMAL state change

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index 4012f0f31517e560ac13692479386a68394bb083..c3907198f0f316d4d727dd81b58f38a6193df570 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -1779,7 +1779,6 @@ void RenderThreadImpl::OnProcessBackgrounded(bool backgrounded) {
     record_purge_suspend_metric_closure_.Reset(
         base::Bind(&RenderThreadImpl::RecordPurgeAndSuspendMetrics,
                    base::Unretained(this)));
-    is_renderer_suspended_ = false;
   }
 }
 
@@ -1788,7 +1787,6 @@ void RenderThreadImpl::OnProcessPurgeAndSuspend() {
   DCHECK(!is_renderer_suspended_);
   if (!RendererIsHidden())
     return;
-  is_renderer_suspended_ = true;
   if (base::FeatureList::IsEnabled(features::kPurgeAndSuspend)) {
     // TODO(tasak): After enabling MemoryCoordinator, remove this Notify
     // and follow MemoryCoordinator's request.
@@ -1899,13 +1897,11 @@ void RenderThreadImpl::OnProcessResume() {
   ChildThreadImpl::OnProcessResume();
 
   DCHECK(is_renderer_suspended_);
-  is_renderer_suspended_ = false;
   if (base::FeatureList::IsEnabled(features::kPurgeAndSuspend)) {
     // TODO(tasak): after enabling MemoryCoordinator, remove this Notify
     // and follow MemoryCoordinator's request.
     base::MemoryCoordinatorClientRegistry::GetInstance()->Notify(
         base::MemoryState::NORMAL);
-    renderer_scheduler_->ResumeRenderer();
   }
 }
 
@@ -2297,8 +2293,10 @@ void RenderThreadImpl::OnMemoryStateChange(base::MemoryState state) {
   }
   switch (state) {
     case base::MemoryState::NORMAL:
+      ResumeRendererIfNeeded();
       break;
     case base::MemoryState::THROTTLED:
+      ResumeRendererIfNeeded();
       ReleaseFreeMemory();
       break;
     case base::MemoryState::SUSPENDED:
@@ -2311,12 +2309,26 @@ void RenderThreadImpl::OnMemoryStateChange(base::MemoryState state) {
 }
 
 void RenderThreadImpl::SuspendRenderer() {
+  DCHECK(IsMainThread());
+  // |is_renderer_suspende_| shouldn't be true here, but it could due to IPC
+  // message lag.
+  if (is_renderer_suspended_)

[bashi, 2016/12/16 07:50:39]

Chatted with tasak@ offline and he said we can't DCHECK here due to IPC lag.
Changed to early return.

[tasak, 2016/12/16 07:55:15]

I was trying to remove DCHECK related to is_renderer_suspended. c.f.
https://codereview.chromium.org/2564833002/
I missed checking whether the patch was successfully committed or not...

... the patch removes is_renderer_suspended_, but this CL needs. I will remove
only DCHECK in OnProcessResume and OnProcessPurgeAndSuspend.

[bashi, 2016/12/16 08:03:13]

Thanks for the info. Then we should do early return in
RendererSchedulerImpl::ResumeRenderer(). I'll wait for your CL to land.

+    return;
   OnTrimMemoryImmediately();
   ReleaseFreeMemory();
   ClearMemory();
+  is_renderer_suspended_ = true;
   renderer_scheduler_->SuspendRenderer();
 }
 
+void RenderThreadImpl::ResumeRendererIfNeeded() {
+  DCHECK(IsMainThread());
+  if (!is_renderer_suspended_)
+    return;
+  renderer_scheduler_->ResumeRenderer();
+  is_renderer_suspended_ = false;
+}
+
 void RenderThreadImpl::ClearMemory() {
   // Do not call into blink if it is not initialized.
   if (blink_platform_impl_) {