Add GPU memory tab to the task manager.

content/gpu/gpu_child_thread.cc

Index: content/gpu/gpu_child_thread.cc
diff --git a/content/gpu/gpu_child_thread.cc b/content/gpu/gpu_child_thread.cc
index 76f482efcc4052d0d60d2ac1a5badf965e9e549a..62eb2aa52239942782167077b6a84db9841e6608 100644
--- a/content/gpu/gpu_child_thread.cc
+++ b/content/gpu/gpu_child_thread.cc
@@ -98,6 +98,7 @@ bool GpuChildThread::OnControlMessageReceived(const IPC::Message& msg) {
   IPC_BEGIN_MESSAGE_MAP_EX(GpuChildThread, msg, msg_is_ok)
     IPC_MESSAGE_HANDLER(GpuMsg_Initialize, OnInitialize)
     IPC_MESSAGE_HANDLER(GpuMsg_CollectGraphicsInfo, OnCollectGraphicsInfo)
+    IPC_MESSAGE_HANDLER(GpuMsg_GetVidmemUsageStats, OnGetVidmemUsageStats)
     IPC_MESSAGE_HANDLER(GpuMsg_Clean, OnClean)
     IPC_MESSAGE_HANDLER(GpuMsg_Crash, OnCrash)
     IPC_MESSAGE_HANDLER(GpuMsg_Hang, OnHang)
@@ -216,6 +217,15 @@ void GpuChildThread::OnCollectGraphicsInfo() {
   Send(new GpuHostMsg_GraphicsInfoCollected(gpu_info_));
 }
 
+void GpuChildThread::OnGetVidmemUsageStats()
+{
+  content::GPUVidmemUsageStats vidmem_usage_stats;
+  if (gpu_channel_manager_.get())
+    gpu_channel_manager_->gpu_memory_manager()->GetVidmemUsageStats(
+        vidmem_usage_stats);
+  Send(new GpuHostMsg_VidmemUsageStats(vidmem_usage_stats));
+}
+
 void GpuChildThread::OnClean() {
   VLOG(1) << "GPU: Removing all contexts";
   if (gpu_channel_manager_.get())