Clean up GestureEventDetails constructors

ui/events/gesture_event_details.cc

 // Copyright 2014 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 "ui/events/gesture_event_details.h"
 
 namespace ui {
 
 GestureEventDetails::GestureEventDetails()
     : type_(ET_UNKNOWN), touch_points_(0), oldest_touch_id_(-1) {
 }
 
+GestureEventDetails::GestureEventDetails(ui::EventType type)
+    : type_(type), touch_points_(1), oldest_touch_id_(0) {
+  DCHECK_GE(type, ET_GESTURE_TYPE_START);
+  DCHECK_LE(type, ET_GESTURE_TYPE_END);

[tdresser, 2014/09/12 12:35:27]

I think it would be worth DCHECKING that this isn't a gesture type which should
be using the other constructor.

DCHECK_NE(type, ET_GESTURE_SCROLL_BEGIN);
DCHECK_NE(type, ET_GESTURE_SCROLL_UPDATE);
etc.

+}
+
 GestureEventDetails::GestureEventDetails(ui::EventType type,
                                          float delta_x,
                                          float delta_y)
     : type_(type), touch_points_(1), oldest_touch_id_(0) {

[jdduke (slow), 2014/09/11 23:37:56]

I wonder why oldest_touch_id_ is 0 here (and in the new constructor), but -1 in
the empty constructor? Seems like it might make it harder to validate that we're
always assigning the value (where it's used, I think only on Aura?). tdresser@,
thoughts?

[tdresser, 2014/09/12 12:35:27]

Yeah, we should always initialize it to -1.

[lanwei, 2014/09/12 14:58:52]

Done.

[lanwei, 2014/09/12 14:58:52]

Done.

   DCHECK_GE(type, ET_GESTURE_TYPE_START);
   DCHECK_LE(type, ET_GESTURE_TYPE_END);
   switch (type_) {
     case ui::ET_GESTURE_SCROLL_BEGIN:
       data.scroll_begin.x_hint = delta_x;
       data.scroll_begin.y_hint = delta_y;
       break;
 
     case ui::ET_GESTURE_SCROLL_UPDATE:
       data.scroll_update.x = delta_x;
       data.scroll_update.y = delta_y;
       break;
 
     case ui::ET_SCROLL_FLING_START:
       data.fling_velocity.x = delta_x;
       data.fling_velocity.y = delta_y;
       break;
 
     case ui::ET_GESTURE_TWO_FINGER_TAP:
       data.first_finger_enclosing_rectangle.width = delta_x;
       data.first_finger_enclosing_rectangle.height = delta_y;
       break;
 
-    case ui::ET_GESTURE_PINCH_UPDATE:
-      data.scale = delta_x;
-      CHECK_EQ(0.f, delta_y) << "Unknown data in delta_y for pinch";
-      break;
-
     case ui::ET_GESTURE_SWIPE:
       data.swipe.left = delta_x < 0;
       data.swipe.right = delta_x > 0;
       data.swipe.up = delta_y < 0;
       data.swipe.down = delta_y > 0;
       break;
 
-    case ui::ET_GESTURE_TAP:
-    case ui::ET_GESTURE_DOUBLE_TAP:
-    case ui::ET_GESTURE_TAP_UNCONFIRMED:
-      data.tap_count = static_cast<int>(delta_x);
-      CHECK_EQ(0.f, delta_y) << "Unknown data in delta_y for tap.";
-      break;
-
     default:
-      if (delta_x != 0.f || delta_y != 0.f) {
-        DLOG(WARNING) << "A gesture event (" << type << ") had unknown data: ("
-                      << delta_x << "," << delta_y;
-      }
-      break;
+      NOTREACHED();
   }
 }
 
 GestureEventDetails::Details::Details() {
   memset(this, 0, sizeof(Details));
 }
 
 }  // namespace ui