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..932ee13c8d832618ae2ba2d0b7ca2c8f0911144c 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_->SuspendRenderer();
 }
 
 void RenderThreadImpl::OnCreateNewFrame(FrameMsg_NewFrame_Params params) {