Move mus::InputEventHandler implementation and tests from PlatformWindowMus to NativeWidgetMus

ui/views/mus/platform_window_mus.cc

Index: ui/views/mus/platform_window_mus.cc
diff --git a/ui/views/mus/platform_window_mus.cc b/ui/views/mus/platform_window_mus.cc
index 99fa1709e15c27778b7590380753f89b4aeb8c8a..ac8c1e071b0841d9cc01346fba8942db4a088348 100644
--- a/ui/views/mus/platform_window_mus.cc
+++ b/ui/views/mus/platform_window_mus.cc
@@ -4,7 +4,6 @@
 
 #include "ui/views/mus/platform_window_mus.h"
 
-#include "base/message_loop/message_loop.h"
 #include "build/build_config.h"
 #include "components/bitmap_uploader/bitmap_uploader.h"
 #include "components/mus/public/cpp/property_type_converters.h"
@@ -23,44 +22,6 @@ namespace {
 
 static uint32_t accelerated_widget_count = 1;
 
-// Handles acknowledgement of an input event, either immediately when a nested
-// message loop starts, or upon destruction.
-class EventAckHandler : public base::MessageLoop::NestingObserver {
- public:
-  explicit EventAckHandler(
-      std::unique_ptr<base::Callback<void(EventResult)>> ack_callback)
-      : ack_callback_(std::move(ack_callback)) {
-    DCHECK(ack_callback_);
-    base::MessageLoop::current()->AddNestingObserver(this);
-  }
-
-  ~EventAckHandler() override {
-    base::MessageLoop::current()->RemoveNestingObserver(this);
-    if (ack_callback_) {
-      ack_callback_->Run(handled_ ? EventResult::HANDLED
-                                  : EventResult::UNHANDLED);
-    }
-  }
-
-  void set_handled(bool handled) { handled_ = handled; }
-
-  // base::MessageLoop::NestingObserver:
-  void OnBeginNestedMessageLoop() override {
-    // Acknowledge the event immediately if a nested message loop starts.
-    // Otherwise we appear unresponsive for the life of the nested message loop.
-    if (ack_callback_) {
-      ack_callback_->Run(EventResult::HANDLED);
-      ack_callback_.reset();
-    }
-  }
-
- private:
-  std::unique_ptr<base::Callback<void(EventResult)>> ack_callback_;
-  bool handled_ = false;
-
-  DISALLOW_COPY_AND_ASSIGN(EventAckHandler);
-};
-
 }  // namespace
 
 PlatformWindowMus::PlatformWindowMus(ui::PlatformWindowDelegate* delegate,
@@ -71,7 +32,6 @@ PlatformWindowMus::PlatformWindowMus(ui::PlatformWindowDelegate* delegate,
       mus_window_destroyed_(false) {
   DCHECK(delegate_);
   DCHECK(mus_window_);
-  mus_window_->set_input_event_handler(this);
 
   // We need accelerated widget numbers to be different for each
   // window and fit in the smallest sizeof(AcceleratedWidget) uint32_t
@@ -93,11 +53,7 @@ PlatformWindowMus::PlatformWindowMus(ui::PlatformWindowDelegate* delegate,
       bitmap_uploader_.get()));
 }
 
-PlatformWindowMus::~PlatformWindowMus() {
-  if (!mus_window_)
-    return;
-  mus_window_->set_input_event_handler(nullptr);
-}
+PlatformWindowMus::~PlatformWindowMus() {}
 
 void PlatformWindowMus::Show() {}
 
@@ -151,19 +107,4 @@ ui::PlatformImeController* PlatformWindowMus::GetPlatformImeController() {
   return nullptr;
 }
 
-void PlatformWindowMus::OnWindowInputEvent(
-    mus::Window* view,
-    const ui::Event& event_in,
-    std::unique_ptr<base::Callback<void(EventResult)>>* ack_callback) {
-  // Take ownership of the callback, indicating that we will handle it.
-  EventAckHandler ack_handler(std::move(*ack_callback));
-
-  std::unique_ptr<ui::Event> event = ui::Event::Clone(event_in);
-  delegate_->DispatchEvent(event.get());
-  // NOTE: |this| may be deleted.
-
-  ack_handler.set_handled(event->handled());
-  // |ack_handler| acks the event on destruction if necessary.
-}
-
 }  // namespace views