Cleanup GpuMemoryBuffer

content/common/gpu/client/gpu_channel_host.cc

Index: content/common/gpu/client/gpu_channel_host.cc
diff --git a/content/common/gpu/client/gpu_channel_host.cc b/content/common/gpu/client/gpu_channel_host.cc
index f7f5d823eedb84285f08f16f93c8b609bcd80793..ea02803efa7f1ce84dd6dd3e9a9534a99d075800 100644
--- a/content/common/gpu/client/gpu_channel_host.cc
+++ b/content/common/gpu/client/gpu_channel_host.cc
@@ -6,6 +6,7 @@
 
 #include <algorithm>
 
+#include "base/barrier_closure.h"
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/message_loop/message_loop.h"
@@ -319,6 +320,18 @@ int32 GpuChannelHost::GenerateRouteID() {
   return next_route_id_.GetNext();
 }
 
+void GpuChannelHost::WaitForPendingGpuMemoryBufferUsageToComplete(
+    const base::Closure& callback) {
+  base::Closure proxy_barrier_closure =
+      base::BarrierClosure(proxies_.size(), callback);
+
+  AutoLock lock(context_lock_);
+  for (ProxyMap::iterator it = proxies_.begin(); it != proxies_.end(); it++) {
+    it->second->WaitForPendingGpuMemoryBufferUsageToComplete(
+        proxy_barrier_closure);
+  }
+}
+
 GpuChannelHost::~GpuChannelHost() {
   // channel_ must be destroyed on the main thread.
   if (!factory_->IsMainThread())