GPU Channel's now maintain a global order number for each processed IPC.

content/common/gpu/gpu_channel_manager.cc

Index: content/common/gpu/gpu_channel_manager.cc
diff --git a/content/common/gpu/gpu_channel_manager.cc b/content/common/gpu/gpu_channel_manager.cc
index 1f027783eb02dc5b839f150f1181872dde49cfd8..da22d4dc4da95dfc358c0541df66d738075fe600 100644
--- a/content/common/gpu/gpu_channel_manager.cc
+++ b/content/common/gpu/gpu_channel_manager.cc
@@ -255,16 +255,19 @@ bool GpuChannelManager::HandleMessagesScheduled() {
   return false;
 }
 
-uint64 GpuChannelManager::MessagesProcessed() {
-  uint64 messages_processed = 0;
-  for (auto& kv : gpu_channels_)
-    messages_processed += kv.second->messages_processed();
-  return messages_processed;
+uint32_t GpuChannelManager::ProcessedOrderNumber() {
+  uint32_t processed_order_num = 0;
+  for (auto& kv : gpu_channels_) {
+    processed_order_num = std::max(processed_order_num,
+                                   kv.second->GetProcessedOrderNum());
+  }
+  return processed_order_num;
 }
 
 void GpuChannelManager::LoseAllContexts() {
-  for (auto& kv : gpu_channels_)
+  for (auto& kv : gpu_channels_) {
     kv.second->MarkAllContextsLost();
+  }
   task_runner_->PostTask(FROM_HERE,
                          base::Bind(&GpuChannelManager::OnLoseAllContexts,
                                     weak_factory_.GetWeakPtr()));