touch-event queue: Add a touch-event queue for all platforms.

content/browser/renderer_host/touch_event_queue.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/renderer_host/touch_event_queue.h"
+
+#include "content/browser/renderer_host/render_widget_host_impl.h"
+#include "content/public/browser/render_widget_host_view.h"
+#include "content/port/browser/render_widget_host_view_port.h"
+
+namespace content {
+
+TouchEventQueue::TouchEventQueue(RenderWidgetHostImpl* host)
+    : render_widget_host_(host) {
+}
+
+TouchEventQueue::~TouchEventQueue() {
+}
+
+void TouchEventQueue::QueueEvent(const WebKit::WebTouchEvent& event) {
+  if (touch_queue_.empty()) {
+    // There is no touch event in the queue. Forward it to the renderer
+    // immediately.
+    touch_queue_.push_back(event);
+    render_widget_host_->ForwardTouchEventImmediately(event);
+    return;
+  }
+
+  // TODO(sad): Coalesce with |touch_queue_.back()| if appropriate.
+  // http://crbug.com/110231
+  touch_queue_.push_back(event);
+}
+
+void TouchEventQueue::ProcessTouchAck(bool processed) {
+  CHECK(!touch_queue_.empty());
+  WebKit::WebTouchEvent acked_event = touch_queue_.front();
+  touch_queue_.pop_front();
+
+  // Note that acking the touch-event may result in multiple gestures being sent
+  // to the renderer.
+  RenderWidgetHostViewPort* view = RenderWidgetHostViewPort::FromRWHV(
+      render_widget_host_->GetView());
+  view->ProcessAckedTouchEvent(acked_event, processed);
+
+  // If there's a queued touch-event, then forward it to the renderer now.
+  if (!touch_queue_.empty())
+    render_widget_host_->ForwardTouchEventImmediately(touch_queue_.front());
+}
+
+}  // namespace content