Revert of discardable_memory: Using mojo IPC to replace Chrome IPC

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 3ae504a137971e138fdb33d683652419a05aa2bf..8616dbdfd1c22b389660eb92cf4314797a34a306 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -881,18 +881,11 @@
 
   categorized_worker_pool_->Start(num_raster_threads);
 
-  discardable_memory::mojom::DiscardableSharedMemoryManagerPtr manager_ptr;
-  ChildThread::Get()->GetRemoteInterfaces()->GetInterface(
-      mojo::GetProxy(&manager_ptr));
-  discardable_shared_memory_manager_ = base::MakeUnique<
-      discardable_memory::ClientDiscardableSharedMemoryManager>(
-      std::move(manager_ptr), GetIOTaskRunner());
-
   // TODO(boliu): In single process, browser main loop should set up the
   // discardable memory manager, and should skip this if kSingleProcess.
   // See crbug.com/503724.
   base::DiscardableMemoryAllocator::SetInstance(
-      discardable_shared_memory_manager_.get());
+      ChildThreadImpl::discardable_shared_memory_manager());
 
   GetContentClient()->renderer()->ExposeInterfacesToBrowser(
       GetInterfaceRegistry());
@@ -1047,7 +1040,7 @@
   // Delay shutting down DiscardableSharedMemoryManager until blink::shutdown
   // is complete, because blink::shutdown destructs Blink Resources and they
   // may try to unlock their underlying discardable memory.
-  discardable_shared_memory_manager_.reset();
+  ChildThreadImpl::ShutdownDiscardableSharedMemoryManager();
 
   // The message loop must be cleared after shutting down
   // the DiscardableSharedMemoryManager, which needs to send messages
@@ -1874,7 +1867,8 @@
                           malloc_usage / 1024 / 1024);
 
   discardable_memory::ClientDiscardableSharedMemoryManager::Statistics
-      discardable_stats = discardable_shared_memory_manager_->GetStatistics();
+      discardable_stats =
+          ChildThreadImpl::discardable_shared_memory_manager()->GetStatistics();
   size_t discardable_usage =
       discardable_stats.total_size - discardable_stats.freelist_size;
   UMA_HISTOGRAM_MEMORY_KB("PurgeAndSuspend.Memory.DiscardableKB",
@@ -2449,7 +2443,7 @@
 
 void RenderThreadImpl::ReleaseFreeMemory() {
   base::allocator::ReleaseFreeMemory();
-  discardable_shared_memory_manager_->ReleaseFreeMemory();
+  discardable_shared_memory_manager()->ReleaseFreeMemory();
 
   if (blink_platform_impl_)
     blink::decommitFreeableMemory();