Update legacy Tuple-using code.

content/browser/renderer_host/input/touch_input_browsertest.cc

Index: content/browser/renderer_host/input/touch_input_browsertest.cc
diff --git a/content/browser/renderer_host/input/touch_input_browsertest.cc b/content/browser/renderer_host/input/touch_input_browsertest.cc
index 3a9f2fd734e897e16540dea87ab50ddca9f8c888..d3032717674afeb8705065f570a0d41cae8a2cfa 100644
--- a/content/browser/renderer_host/input/touch_input_browsertest.cc
+++ b/content/browser/renderer_host/input/touch_input_browsertest.cc
@@ -112,8 +112,8 @@ class InputEventMessageFilter : public BrowserMessageFilter {
     if (message.type() == InputHostMsg_HandleInputEvent_ACK::ID) {
       InputHostMsg_HandleInputEvent_ACK::Param params;
       InputHostMsg_HandleInputEvent_ACK::Read(&message, &params);
-      WebInputEvent::Type type = params.a.type;
-      InputEventAckState ack = params.a.state;
+      WebInputEvent::Type type = get<0>(params).type;
+      InputEventAckState ack = get<0>(params).state;
       BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
           base::Bind(&InputEventMessageFilter::ReceivedEventAck,
                      this, type, ack));