Experimental 'purging and suspending' backgrounded tabs behind the flag

content/renderer/render_thread_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <utility>
@@ skipping 804 matching lines @@
   // We may not have a MojoShellConnection object in tests that directly
   // instantiate a RenderThreadImpl.
   if (MojoShellConnection::Get() &&
       base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kUseMusInRenderer))
     CreateRenderWidgetWindowTreeClientFactory();
 #endif
 
   service_registry()->ConnectToRemoteService(
       mojo::GetProxy(&storage_partition_service_));
+
+  is_renderer_suspended_ = false;
 }
 
 RenderThreadImpl::~RenderThreadImpl() {
 }
 
 void RenderThreadImpl::Shutdown() {
   FOR_EACH_OBSERVER(
       RenderThreadObserver, observers_, OnRenderProcessShutdown());
 
   if (memory_observer_) {
@@ skipping 865 matching lines @@
     IPC_MESSAGE_HANDLER(ViewMsg_PurgePluginListCache, OnPurgePluginListCache)
 #endif
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void RenderThreadImpl::OnProcessBackgrounded(bool backgrounded) {
   ChildThreadImpl::OnProcessBackgrounded(backgrounded);
 
-  if (backgrounded)
+  if (backgrounded) {
     renderer_scheduler_->OnRendererBackgrounded();
-  else
+  } else {
     renderer_scheduler_->OnRendererForegrounded();
+    is_renderer_suspended_ = false;
+  }
+}
+
+void RenderThreadImpl::OnProcessPurgeAndSuspend() {
+  ChildThreadImpl::OnProcessPurgeAndSuspend();
+  if (is_renderer_suspended_)
+    return;
+  // TODO(hajimehoshi): Implement purging e.g. cache (crbug/607077)
+  is_renderer_suspended_ = true;
+  renderer_scheduler_->SuspendRenderer();
 }
 
 void RenderThreadImpl::OnCreateNewFrame(FrameMsg_NewFrame_Params params) {
   CompositorDependencies* compositor_deps = this;
   RenderFrameImpl::CreateFrame(
       params.routing_id, params.proxy_routing_id, params.opener_routing_id,
       params.parent_routing_id, params.previous_sibling_routing_id,
       params.replication_state, compositor_deps, params.widget_params,
       params.frame_owner_properties);
 }
@@ skipping 366 matching lines @@
       v8_memory_pressure_level == v8::MemoryPressureLevel::kCritical)
     v8_memory_pressure_level = v8::MemoryPressureLevel::kModerate;
 
   blink::mainThreadIsolate()->MemoryPressureNotification(
       v8_memory_pressure_level);
   blink::MemoryPressureNotificationToWorkerThreadIsolates(
       v8_memory_pressure_level);
 }
 
 }  // namespace content