Revert of Overhaul Mandoline event transport code

components/mus/display_manager.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 "components/mus/display_manager.h"
 
 #include "base/numerics/safe_conversions.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/delegated_frame_data.h"
 #include "cc/quads/render_pass.h"
@@ skipping 63 matching lines @@
       quad_to_target_transform, bounds_at_origin.size() /* layer_bounds */,
       bounds_at_origin /* visible_layer_bounds */,
       bounds_at_origin /* clip_rect */, false /* is_clipped */, view->opacity(),
       SkXfermode::kSrc_Mode, 0 /* sorting-context_id */);
 
   auto surface_quad = pass->CreateAndAppendDrawQuad<cc::SurfaceDrawQuad>();
   surface_quad->SetNew(sqs, bounds_at_origin /* rect */,
                        bounds_at_origin /* visible_rect */, view->surface_id());
 }
 
+float ConvertUIWheelValueToMojoValue(int offset) {
+  // Mojo's event type takes a value between -1 and 1. Normalize by allowing
+  // up to 20 of ui's offset. This is a bit arbitrary.
+  return std::max(
+      -1.0f, std::min(1.0f, static_cast<float>(offset) /
+                                (20 * static_cast<float>(
+                                          ui::MouseWheelEvent::kWheelDelta))));
+}
+
 }  // namespace
 
 // static
 DisplayManagerFactory* DisplayManager::factory_ = nullptr;
 
 // static
 DisplayManager* DisplayManager::Create(
     bool is_headless,
     mojo::ApplicationImpl* app_impl,
     const scoped_refptr<gles2::GpuState>& gpu_state,
@@ skipping 156 matching lines @@
   UpdateMetrics(new_bounds.size(), metrics_.device_pixel_ratio);
 }
 
 void DefaultDisplayManager::OnDamageRect(const gfx::Rect& damaged_region) {
   dirty_rect_.Union(damaged_region);
   WantToDraw();
 }
 
 void DefaultDisplayManager::DispatchEvent(ui::Event* event) {
   mojo::EventPtr mojo_event(mojo::Event::From(*event));
+  if (event->IsMouseWheelEvent()) {
+    // Mojo's event type has a different meaning for wheel events. Convert
+    // between the two.
+    ui::MouseWheelEvent* wheel_event = static_cast<ui::MouseWheelEvent*>(event);
+    DCHECK(mojo_event->pointer_data);
+    mojo_event->pointer_data->horizontal_wheel =
+        ConvertUIWheelValueToMojoValue(wheel_event->x_offset());
+    mojo_event->pointer_data->horizontal_wheel =
+        ConvertUIWheelValueToMojoValue(wheel_event->y_offset());
+  }
   delegate_->OnEvent(mojo_event.Pass());
 
   switch (event->type()) {
     case ui::ET_MOUSE_PRESSED:
     case ui::ET_TOUCH_PRESSED:
       platform_window_->SetCapture();
       break;
     case ui::ET_MOUSE_RELEASED:
     case ui::ET_TOUCH_RELEASED:
       platform_window_->ReleaseCapture();
@@ skipping 54 matching lines @@
   if (widget != gfx::kNullAcceleratedWidget) {
     top_level_display_client_.reset(new surfaces::TopLevelDisplayClient(
         widget, gpu_state_, surfaces_state_));
   }
   UpdateMetrics(metrics_.size_in_pixels.To<gfx::Size>(), device_pixel_ratio);
 }
 
 void DefaultDisplayManager::OnActivationChanged(bool active) {}
 
 }  // namespace view_manager