Add ChildMemoryCoordinator::PurgeMemory()

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 45678d19a939b0bec6864ddc6aca43a1d66fc21f..fcd2444be29c2ade42b7a40228bc2712d0d65e86 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -1670,10 +1670,7 @@ void RenderThreadImpl::OnProcessPurgeAndSuspend() {
     return;
 
   if (base::FeatureList::IsEnabled(features::kPurgeAndSuspend)) {
-    // TODO(tasak): After enabling MemoryCoordinator, remove this Notify
-    // and follow MemoryCoordinator's request.
-    base::MemoryCoordinatorClientRegistry::GetInstance()->Notify(
-        base::MemoryState::SUSPENDED);
+    memory_coordinator_->PurgeMemory();

[Wez, 2017/02/15 19:51:58]

Isn't |memory_coordinator_| only initialized if MemoryCoordinator is enabled,
which is mutually exclusive with PurgeAndSuspend, according to the DCHECK at
line 826?

   }
   // 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