Prepare SyntheticPointerAction to handle mouse actions

content/common/input/synthetic_pointer_action_params.cc

 // 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/common/input/synthetic_pointer_action_params.h"
 
 namespace content {
 
 SyntheticPointerActionParams::SyntheticPointerActionParams()
-    : pointer_action_type_(PointerActionType::NOT_INITIALIZED), index_(-1) {}
+    : pointer_action_type_(PointerActionType::NOT_INITIALIZED), index_(0) {}
 
 SyntheticPointerActionParams::SyntheticPointerActionParams(
     PointerActionType type)
-    : pointer_action_type_(type), index_(-1) {}

[tdresser, 2016/07/26 12:27:41]

Do we ever end up with -1 in the index_map_ now? If not, none of the validation
code will work, will it?

[lanwei, 2016/07/28 04:47:23]

In the constructor, the sourcetype is unknown. How about I always return 0?

[tdresser, 2016/07/28 12:29:55]

I'm not clear on what your proposal is here. If you always return 0, validation
logic doesn't work, correct? (Don't we have a test that should fail in this
case?)

We could change the variable to be called "touch_index_", or something, and then
have a method called "index()" which, if the source is touch, returns the
touch_index_, and otherwise returns 0.

+    : pointer_action_type_(type), index_(0) {}
 
 SyntheticPointerActionParams::SyntheticPointerActionParams(
     const SyntheticPointerActionParams& other)
     : SyntheticGestureParams(other),
       pointer_action_type_(other.pointer_action_type()) {
   switch (other.pointer_action_type()) {
     case PointerActionType::PRESS:
     case PointerActionType::MOVE:
       index_ = other.index();
       position_ = other.position();
@@ skipping 14 matching lines @@
 }
 
 const SyntheticPointerActionParams* SyntheticPointerActionParams::Cast(
     const SyntheticGestureParams* gesture_params) {
   DCHECK(gesture_params);
   DCHECK_EQ(POINTER_ACTION, gesture_params->GetGestureType());
   return static_cast<const SyntheticPointerActionParams*>(gesture_params);
 }
 
 }  // namespace content