Experimental 'purging and suspending' backgrounded tabs behind the flag

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 c81e108be2fee15ac2e233e91f3a4035618ed098..cb92fc64457ec55190201ffa036cdde30d9e406c 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -811,6 +811,8 @@ void RenderThreadImpl::Init(
 
   service_registry()->ConnectToRemoteService(
       mojo::GetProxy(&storage_partition_service_));
+
+  is_cache_purged_ = false;
 }
 
 RenderThreadImpl::~RenderThreadImpl() {
@@ -1679,10 +1681,21 @@ bool RenderThreadImpl::OnControlMessageReceived(const IPC::Message& msg) {
 void RenderThreadImpl::OnProcessBackgrounded(bool backgrounded) {
   ChildThreadImpl::OnProcessBackgrounded(backgrounded);
 
-  if (backgrounded)
+  if (backgrounded) {
     renderer_scheduler_->OnRendererBackgrounded();
-  else
+  } else {
     renderer_scheduler_->OnRendererForegrounded();
+    is_cache_purged_ = false;
+  }
+}
+
+void RenderThreadImpl::OnProcessPurgeAndSuspend() {
+  ChildThreadImpl::OnProcessPurgeAndSuspend();
+  if (is_cache_purged_)
+    return;
+  // TODO(hajimehoshi): Implement purging e.g. cache (crbug/607077)
+  is_cache_purged_ = true;
+  renderer_scheduler_->SuspendRendererWhenBackgrounded();

[dcheng, 2016/05/10 16:28:06]

Will we ever send a "purge and suspend" to a non-background renderer?

[hajimehoshi, 2016/05/11 07:23:31]

Good point. Done by adding |is_backgrounded_|.

 }
 
 void RenderThreadImpl::OnCreateNewFrame(FrameMsg_NewFrame_Params params) {