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 153 matching lines @@
     }
     delegate_->OnPointerFrame();
   }
 
   // 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;
   }
 
+  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();
+      delegate_->OnPointerMotion(event->time_stamp(), location_);
+      send_frame = true;
+    }
+    if (stylus_delegate_ &&
+        pointer_type_ != ui::EventPointerType::POINTER_TYPE_MOUSE) {
+      constexpr float kEpsilon = std::numeric_limits<float>::epsilon();
+      gfx::Vector2dF new_tilt = gfx::Vector2dF(event->pointer_details().tilt_x,
+                                               event->pointer_details().tilt_y);
+      if (std::abs(new_tilt.x() - tilt_.x()) > kEpsilon ||
+          std::abs(new_tilt.y() - tilt_.y()) > kEpsilon) {
+        tilt_ = new_tilt;
+        stylus_delegate_->OnPointerTilt(event->time_stamp(), new_tilt);
+        send_frame = true;
+      }
+
+      float new_force = event->pointer_details().force;
+      if (std::abs(new_force - force_) > kEpsilon) {
+        force_ = new_force;
+        stylus_delegate_->OnPointerForce(event->time_stamp(), new_force);
+        send_frame = true;
+      }
+    }
+    if (send_frame)
+      delegate_->OnPointerFrame();

[reveman, 2016/09/16 17:36:29]

nit: can we delay this until after the switch statement and avoid sending
multiple frame events?

+  }
+
   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();
-          delegate_->OnPointerMotion(event->time_stamp(), location_);
-          send_frame = true;
-        }
-        if (stylus_delegate_ &&
-            pointer_type_ != ui::EventPointerType::POINTER_TYPE_MOUSE) {
-          constexpr float kEpsilon = std::numeric_limits<float>::epsilon();
-          gfx::Vector2dF new_tilt = gfx::Vector2dF(
-              event->pointer_details().tilt_x, event->pointer_details().tilt_y);
-          if (std::abs(new_tilt.x() - tilt_.x()) > kEpsilon ||
-              std::abs(new_tilt.y() - tilt_.y()) > kEpsilon) {
-            tilt_ = new_tilt;
-            stylus_delegate_->OnPointerTilt(event->time_stamp(), new_tilt);
-            send_frame = true;
-          }
-
-          float new_force = event->pointer_details().force;
-          if (std::abs(new_force - force_) > kEpsilon) {
-            force_ = new_force;
-            stylus_delegate_->OnPointerForce(event->time_stamp(), new_force);
-            send_frame = true;
-          }
-        }
-        if (send_frame)
-          delegate_->OnPointerFrame();
-      }
-      break;
     case ui::ET_SCROLL:
       if (focus_) {
         ui::ScrollEvent* scroll_event = static_cast<ui::ScrollEvent*>(event);
         delegate_->OnPointerScroll(
             event->time_stamp(),
             gfx::Vector2dF(scroll_event->x_offset(), scroll_event->y_offset()),
             false);
         delegate_->OnPointerFrame();
       }
       break;
@@ skipping 10 matching lines @@
         delegate_->OnPointerScrollStop(event->time_stamp());
         delegate_->OnPointerFrame();
       }
       break;
     case ui::ET_SCROLL_FLING_CANCEL:
       if (focus_) {
         delegate_->OnPointerScrollCancel(event->time_stamp());
         delegate_->OnPointerFrame();
       }
       break;
+    case ui::ET_MOUSE_MOVED:
+    case ui::ET_MOUSE_DRAGGED:
     case ui::ET_MOUSE_ENTERED:
     case ui::ET_MOUSE_EXITED:
     case ui::ET_MOUSE_CAPTURE_CHANGED:
       break;
     default:
       NOTREACHED();
       break;
   }
 
   if ((event->flags() & ui::EF_IS_SYNTHESIZED) == 0)
@@ skipping 102 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