Improve GamepadSeqLock impl

content/browser/gamepad/gamepad_provider.cc

Index: content/browser/gamepad/gamepad_provider.cc
===================================================================
--- content/browser/gamepad/gamepad_provider.cc	(revision 112429)
+++ content/browser/gamepad/gamepad_provider.cc	(working copy)
@@ -118,16 +118,9 @@
   DCHECK(MessageLoop::current() == polling_thread_->message_loop());
   GamepadHardwareBuffer* hwbuf = SharedMemoryAsHardwareBuffer();
 
-  ANNOTATE_BENIGN_RACE_SIZED(
-      &hwbuf->buffer,
-      sizeof(WebKit::WebGamepads),
-      "Racey reads are discarded");
-
-  // Acquire the SeqLock. There is only ever one writer to this data.
-  // See gamepad_hardware_buffer.h.
-  hwbuf->sequence.WriteBegin();
-  data_fetcher_->GetGamepadData(&hwbuf->buffer, devices_changed_);
-  hwbuf->sequence.WriteEnd();
+  WebKit::WebGamepads tmp;
+  data_fetcher_->GetGamepadData(&tmp, devices_changed_);
+  hwbuf->gamepads.Write(&tmp);
   devices_changed_ = false;
   // Schedule our next interval of polling.
   ScheduleDoPoll();