Expose Resume() in RenderProcessHost.

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 6ca91bed3a272b90adb6bde4aa7d0e2ec2715f07..7296ab1965a7c5116af4244b3ebf7c479521b458 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -1766,7 +1766,7 @@ void RenderThreadImpl::OnProcessBackgrounded(bool backgrounded) {
 
 void RenderThreadImpl::OnProcessPurgeAndSuspend() {
   ChildThreadImpl::OnProcessPurgeAndSuspend();
-  if (is_renderer_suspended_)
+  if (is_renderer_suspended_ || !RendererIsHidden())

[dcheng, 2016/10/27 05:51:40]

(I wonder if this should also be a DCHECK for the is_renderer_suspended_ bit)

[tasak, 2016/10/27 08:52:03]

Acknowledged.
Currently TabManager sends PurgeAndSuspend message periodically (every
purge-and-suspend-time seconds)...
I will replace this with DCHECK(!is_renderer_suspended_) after committing
TabManager's patch.

     return;
   // TODO(hajimehoshi): Implement purging e.g. cache (crbug/607077)
   is_renderer_suspended_ = true;
@@ -1877,6 +1877,14 @@ void RenderThreadImpl::RecordPurgeAndSuspendMetrics() const {
                               1024 / 1024);
 }
 
+void RenderThreadImpl::OnProcessResume() {
+  ChildThreadImpl::OnProcessResume();
+
+  DCHECK(is_renderer_suspended_);
+  is_renderer_suspended_ = false;
+  renderer_scheduler_->ResumeRenderer();
+}
+
 scoped_refptr<gpu::GpuChannelHost> RenderThreadImpl::EstablishGpuChannelSync() {
   TRACE_EVENT0("gpu", "RenderThreadImpl::EstablishGpuChannelSync");