exo: Send pointer location before button event

components/exo/pointer.cc

 // Copyright 2015 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 "components/exo/pointer.h"
 
 #include "ash/common/shell_window_ids.h"
 #include "ash/display/display_manager.h"
 #include "components/exo/pointer_delegate.h"
 #include "components/exo/pointer_stylus_delegate.h"
@@ skipping 156 matching lines @@
 
   // Report changes in pointer type.
   if (focus_ && stylus_delegate_ && new_pointer_type != pointer_type_) {
     stylus_delegate_->OnPointerToolChange(new_pointer_type);
     pointer_type_ = new_pointer_type;
   }
 
   switch (event->type()) {
     case ui::ET_MOUSE_PRESSED:
     case ui::ET_MOUSE_RELEASED:
-      if (focus_) {
-        delegate_->OnPointerButton(event->time_stamp(),
-                                   event->changed_button_flags(),
-                                   event->type() == ui::ET_MOUSE_PRESSED);
-        delegate_->OnPointerFrame();
-      }
-      break;
     case ui::ET_MOUSE_MOVED:
     case ui::ET_MOUSE_DRAGGED:
       if (focus_) {
         bool send_frame = false;
         // Generate motion event if location changed. We need to check location
         // here as mouse movement can generate both "moved" and "entered" events
         // but OnPointerMotion should only be called if location changed since
         // OnPointerEnter was called.
         if (!SameLocation(event, location_)) {
           location_ = event->location_f();
@@ skipping 55 matching lines @@
       break;
     case ui::ET_MOUSE_ENTERED:
     case ui::ET_MOUSE_EXITED:
     case ui::ET_MOUSE_CAPTURE_CHANGED:
       break;
     default:
       NOTREACHED();
       break;
   }
 
+  if (focus_ && (event->type() == ui::ET_MOUSE_PRESSED ||
+                 event->type() == ui::ET_MOUSE_RELEASED)) {
+    delegate_->OnPointerButton(event->time_stamp(),
+                               event->changed_button_flags(),
+                               event->type() == ui::ET_MOUSE_PRESSED);
+    delegate_->OnPointerFrame();
+  }

[reveman, 2016/09/16 17:11:26]

I'm failing to see how this change makes any difference. How is this making use
send the location change event before button press/release events?

+
   if ((event->flags() & ui::EF_IS_SYNTHESIZED) == 0)
     is_direct_input_ = (event->flags() & ui::EF_DIRECT_INPUT) != 0;
 
   // Update cursor widget to reflect current focus and pointer location.
   if (focus_ && !is_direct_input_) {
     if (!widget_)
       CreatePointerWidget();
 
     // Update cursor location if mouse event caused it to change.
     gfx::Point mouse_location = aura::Env::GetInstance()->last_mouse_location();
@@ skipping 93 matching lines @@
 
   if (ui_scale != cursor_scale_) {
     gfx::Transform transform;
     transform.Scale(ui_scale, ui_scale);
     widget_->GetNativeWindow()->SetTransform(transform);
     cursor_scale_ = ui_scale;
   }
 }
 
 }  // namespace exo