diff --git a/ipc/chromium/src/base/message_pump_win.cc b/ipc/chromium/src/base/message_pump_win.cc
index dabb0284f5ec8..52c948ad81d86 100644
--- a/ipc/chromium/src/base/message_pump_win.cc
+++ b/ipc/chromium/src/base/message_pump_win.cc
@@ -452,45 +452,55 @@ void MessagePumpForIO::WaitForWork() {
 }
 
 bool MessagePumpForIO::WaitForIOCompletion(DWORD timeout, IOHandler* filter) {
-  IOItem item;
-  if (completed_io_.empty() || !MatchCompletedIOItem(filter, &item)) {
-    // We have to ask the system for another IO completion.
-    if (!GetIOItem(timeout, &item)) return false;
-
-    if (ProcessInternalIOItem(item)) return true;
+  IOItemChunk items;
+  if (completed_io_.empty() || !MatchCompletedIOItem(filter, items.values)) {
+    if (!GetIOItems(timeout, &items)) return false;
+  } else {
+    items.count = 1;
   }
 
-  if (item.context->handler) {
-    if (filter && item.handler != filter) {
-      // Save this item for later
-      completed_io_.push_back(item);
+  for (ULONG i = 0; i < items.count; ++i) {
+    IOItem& item = items.values[i];
+    if (ProcessInternalIOItem(item)) {
+      continue;
+    }
+
+    if (item.context->handler) {
+      if (filter && item.handler != filter) {
+        // Save this item for later
+        completed_io_.push_back(item);
+      } else {
+        DCHECK(item.context->handler == item.handler);
+        item.handler->OnIOCompleted(item.context, item.bytes_transfered);
+      }
     } else {
-      DCHECK(item.context->handler == item.handler);
-      item.handler->OnIOCompleted(item.context, item.bytes_transfered,
-                                  item.error);
+      // The handler must be gone by now, just cleanup the mess.
+      delete item.context;
     }
-  } else {
-    // The handler must be gone by now, just cleanup the mess.
-    delete item.context;
   }
+
   return true;
 }
 
 // Asks the OS for another IO completion result.
-bool MessagePumpForIO::GetIOItem(DWORD timeout, IOItem* item) {
-  memset(item, 0, sizeof(*item));
-  ULONG_PTR key = 0;
-  OVERLAPPED* overlapped = NULL;
+bool MessagePumpForIO::GetIOItems(DWORD timeout, IOItemChunk* items) {
+  memset(items, 0, sizeof(*items));
+  OVERLAPPED_ENTRY entries[arraysize(items->values)];
   AUTO_PROFILER_LABEL("MessagePumpForIO::GetIOItem::Wait", IDLE);
-  if (!GetQueuedCompletionStatus(port_.Get(), &item->bytes_transfered, &key,
-                                 &overlapped, timeout)) {
-    if (!overlapped) return false;  // Nothing in the queue.
-    item->error = GetLastError();
-    item->bytes_transfered = 0;
+  if (!GetQueuedCompletionStatusEx(port_.Get(), entries,
+                                   arraysize(items->values), &items->count,
+                                   timeout, FALSE)) {
+    return false;  // Nothing in the queue.
+  }
+
+  for (int i = 0; i < (int)items->count; ++i) {
+    items->values[i].handler =
+        reinterpret_cast<IOHandler*>(entries[i].lpCompletionKey);
+    items->values[i].bytes_transfered = entries[i].dwNumberOfBytesTransferred;
+    items->values[i].context =
+        reinterpret_cast<IOContext*>(entries[i].lpOverlapped);
   }
 
-  item->handler = reinterpret_cast<IOHandler*>(key);
-  item->context = reinterpret_cast<IOContext*>(overlapped);
   return true;
 }
 
diff --git a/ipc/chromium/src/base/message_pump_win.h b/ipc/chromium/src/base/message_pump_win.h
index 585a4d3ff5acd..95db3e48004a5 100644
--- a/ipc/chromium/src/base/message_pump_win.h
+++ b/ipc/chromium/src/base/message_pump_win.h
@@ -222,8 +222,8 @@ class MessagePumpForIO : public MessagePumpWin {
   //         delete context_;
   //      }
   //     }
-  //     virtual void OnIOCompleted(IOContext* context, DWORD bytes_transfered,
-  //                                DWORD error) {
+  //     virtual void OnIOCompleted(IOContext* context, DWORD bytes_transfered)
+  //     {
   //         pending_ = false;
   //     }
   //     void DoSomeIo() {
@@ -248,8 +248,8 @@ class MessagePumpForIO : public MessagePumpWin {
   //     // while there are pending IO operations.
   //     ~MyFile() {
   //     }
-  //     virtual void OnIOCompleted(IOContext* context, DWORD bytes_transfered,
-  //                                DWORD error) {
+  //     virtual void OnIOCompleted(IOContext* context, DWORD bytes_transfered)
+  //     {
   //       ...
   //       delete context;
   //     }
@@ -280,8 +280,7 @@ class MessagePumpForIO : public MessagePumpWin {
     // |context| completes. |error| is the Win32 error code of the IO operation
     // (ERROR_SUCCESS if there was no error). |bytes_transfered| will be zero
     // on error.
-    virtual void OnIOCompleted(IOContext* context, DWORD bytes_transfered,
-                               DWORD error) = 0;
+    virtual void OnIOCompleted(IOContext* context, DWORD bytes_transfered) = 0;
   };
 
   // The extended context that should be used as the base structure on every
@@ -326,13 +325,16 @@ class MessagePumpForIO : public MessagePumpWin {
     IOHandler* handler;
     IOContext* context;
     DWORD bytes_transfered;
-    DWORD error;
+  };
+  struct IOItemChunk {
+    IOItem values[8];
+    ULONG count;
   };
 
   virtual void DoRunLoop();
   void WaitForWork();
   bool MatchCompletedIOItem(IOHandler* filter, IOItem* item);
-  bool GetIOItem(DWORD timeout, IOItem* item);
+  bool GetIOItems(DWORD timeout, IOItemChunk* items);
   bool ProcessInternalIOItem(const IOItem& item);
 
   // The completion port associated with this thread.
diff --git a/ipc/chromium/src/chrome/common/ipc_channel_win.cc b/ipc/chromium/src/chrome/common/ipc_channel_win.cc
index 91bd33b6cb974..4ba092f01c7f7 100644
--- a/ipc/chromium/src/chrome/common/ipc_channel_win.cc
+++ b/ipc/chromium/src/chrome/common/ipc_channel_win.cc
@@ -286,7 +286,7 @@ bool Channel::ChannelImpl::Connect() {
     // to true, we indicate to OnIOCompleted that this is the special
     // initialization signal.
     MessageLoopForIO::current()->PostTask(factory_.NewRunnableMethod(
-        &Channel::ChannelImpl::OnIOCompleted, &input_state_.context, 0, 0));
+        &Channel::ChannelImpl::OnIOCompleted, &input_state_.context, 0));
   }
 
   if (!waiting_connect_) ProcessOutgoingMessages(NULL, 0);
@@ -556,7 +556,7 @@ bool Channel::ChannelImpl::ProcessOutgoingMessages(
 }
 
 void Channel::ChannelImpl::OnIOCompleted(MessageLoopForIO::IOContext* context,
-                                         DWORD bytes_transfered, DWORD error) {
+                                         DWORD bytes_transfered) {
   bool ok;
   ASSERT_OWNINGTHREAD(ChannelImpl);
   if (context == &input_state_.context) {
diff --git a/ipc/chromium/src/chrome/common/ipc_channel_win.h b/ipc/chromium/src/chrome/common/ipc_channel_win.h
index ac21c16b8ce8e..54e5d8d2a8952 100644
--- a/ipc/chromium/src/chrome/common/ipc_channel_win.h
+++ b/ipc/chromium/src/chrome/common/ipc_channel_win.h
@@ -68,7 +68,7 @@ class Channel::ChannelImpl : public MessageLoopForIO::IOHandler {
 
   // MessageLoop::IOHandler implementation.
   virtual void OnIOCompleted(MessageLoopForIO::IOContext* context,
-                             DWORD bytes_transfered, DWORD error);
+                             DWORD bytes_transfered);
 
  private:
   struct State {