Make SyntheticPointerAction to flush the pointer action sequence

content/browser/renderer_host/input/synthetic_pointer_action_controller.cc

Index: content/browser/renderer_host/input/synthetic_pointer_action_controller.cc
diff --git a/content/browser/renderer_host/input/synthetic_pointer_action_controller.cc b/content/browser/renderer_host/input/synthetic_pointer_action_controller.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0a3de5e24dd8ed42e125fbead3c265f0c2f9483b
--- /dev/null
+++ b/content/browser/renderer_host/input/synthetic_pointer_action_controller.cc
@@ -0,0 +1,42 @@
+// Copyright 2016 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/input/synthetic_pointer_action_controller.h"
+
+namespace content {
+
+SyntheticPointerActionController::SyntheticPointerActionController() {
+  std::fill(index_map_.begin(), index_map_.end(), -1);
+}
+SyntheticPointerActionController::~SyntheticPointerActionController() {}
+
+std::unique_ptr<SyntheticGesture>
+SyntheticPointerActionController::CreateSyntheticPointerAction(
+    const SyntheticPointerActionListParams& gesture_params) {
+  if (!synthetic_pointer_)
+    SetSyntheticPointer(gesture_params);
+
+  std::unique_ptr<SyntheticGesture> synthetic_gesture =
+      std::unique_ptr<SyntheticGesture>(new SyntheticPointerAction(
+          gesture_params, synthetic_pointer_.get(), &index_map_));
+  return synthetic_gesture;
+}
+
+void SyntheticPointerActionController::SetSyntheticPointer(
+    const SyntheticPointerActionListParams& gesture_params) {
+  SyntheticGestureParams::GestureSourceType gesture_source_type =
+      gesture_params.gesture_source_type;
+  if (gesture_source_type == SyntheticGestureParams::DEFAULT_INPUT) {

[tdresser, 2016/10/26 18:28:40]

If the synthetic pointer was already set, this silently does nothing. Should
there be a DCHECK here?

[lanwei, 2016/10/30 23:23:13]

You mean adding a DCHECK here for gesture_source_type?

[tdresser, 2016/10/31 14:22:57]

I'm proposing we add a DCHECK in the case where gesture_source_type was already
set.

+    gesture_source_type = default_type_;
+  }
+  DCHECK_NE(gesture_source_type, SyntheticGestureParams::DEFAULT_INPUT);
+  synthetic_pointer_ = SyntheticPointer::Create(gesture_source_type);
+}
+
+void SyntheticPointerActionController::SetDefaultGestureSourceType(
+    SyntheticGestureParams::GestureSourceType default_type) {
+  default_type_ = default_type;
+}
+
+}  // namespace content