Resume a backgrounded renderer that was purged and suspended

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 1748 matching lines @@
     renderer_scheduler_->OnRendererBackgrounded();
   } else {
     renderer_scheduler_->OnRendererForegrounded();
     record_purge_suspend_metric_closure_.Cancel();
     is_renderer_suspended_ = false;
   }
 }
 
 void RenderThreadImpl::OnProcessPurgeAndSuspend() {
   ChildThreadImpl::OnProcessPurgeAndSuspend();
-  if (is_renderer_suspended_)
+  if (is_renderer_suspended_ || !RendererIsHidden())
     return;
   // TODO(hajimehoshi): Implement purging e.g. cache (crbug/607077)
   is_renderer_suspended_ = true;
   renderer_scheduler_->SuspendRenderer();
 
   // Since purging is not a synchronous task (e.g. v8 GC, oilpan GC, ...),
   // we need to wait until the task is finished. So wait 15 seconds and
   // update purge+suspend UMA histogram.
   // TODO(tasak): use MemoryCoordinator's callback to report purge+suspend
   // UMA when MemoryCoordinator is available.
@@ skipping 90 matching lines @@
   // memory-infra.
   UMA_HISTOGRAM_MEMORY_MB("PurgeAndSuspend.Memory.V8MainThreadIsolateMB",
                           v8_usage / 1024 / 1024);
   UMA_HISTOGRAM_MEMORY_MB("PurgeAndSuspend.Memory.TotalAllocatedMB",
                           (blink_stats.partitionAllocTotalAllocatedBytes +
                            blink_stats.blinkGCTotalAllocatedBytes +
                            malloc_usage + v8_usage + discardable_usage) /
                               1024 / 1024);
 }
 
+void RenderThreadImpl::OnProcessResume() {
+  ChildThreadImpl::OnProcessResume();
+  if (!is_renderer_suspended_)
+    return;
+
+  is_renderer_suspended_ = false;
+  renderer_scheduler_->ResumeRenderer();
+}
+
 scoped_refptr<gpu::GpuChannelHost> RenderThreadImpl::EstablishGpuChannelSync() {
   TRACE_EVENT0("gpu", "RenderThreadImpl::EstablishGpuChannelSync");
 
   if (gpu_channel_) {
     // Do nothing if we already have a GPU channel or are already
     // establishing one.
     if (!gpu_channel_->IsLost())
       return gpu_channel_;
 
     // Recreate the channel if it has been lost.
@@ skipping 581 matching lines @@
   }
 }
 
 void RenderThreadImpl::OnRendererInterfaceRequest(
     mojom::RendererAssociatedRequest request) {
   DCHECK(!renderer_binding_.is_bound());
   renderer_binding_.Bind(std::move(request));
 }
 
 }  // namespace content