Introduce aura::Env controller to abstract away changes to aura::Env

ui/aura/window_event_dispatcher.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/aura/window_event_dispatcher.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/client/event_client.h"
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/client/screen_position_client.h"
 #include "ui/aura/env.h"
+#include "ui/aura/env_input_state_controller.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/aura/window_targeter.h"
 #include "ui/aura/window_tracker.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/base/hit_test.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/events/event.h"
 #include "ui/events/event_utils.h"
 #include "ui/events/gestures/gesture_recognizer.h"
@@ skipping 11 matching lines @@
   if (!target->delegate())
     return false;
   int hit_test_code = target->delegate()->GetNonClientComponent(location);
   return hit_test_code != HTCLIENT && hit_test_code != HTNOWHERE;
 }
 
 Window* ConsumerToWindow(ui::GestureConsumer* consumer) {
   return consumer ? static_cast<Window*>(consumer) : NULL;
 }
 
-void SetLastMouseLocation(const Window* root_window,
-                          const gfx::Point& location_in_root) {
-  client::ScreenPositionClient* client =
-      client::GetScreenPositionClient(root_window);
-  if (client) {
-    gfx::Point location_in_screen = location_in_root;
-    client->ConvertPointToScreen(root_window, &location_in_screen);
-    Env::GetInstance()->set_last_mouse_location(location_in_screen);
-  } else {
-    Env::GetInstance()->set_last_mouse_location(location_in_root);
-  }
-}
-
 bool IsEventCandidateForHold(const ui::Event& event) {
   if (event.type() == ui::ET_TOUCH_MOVED)
     return true;
   if (event.type() == ui::ET_MOUSE_DRAGGED)
     return true;
   if (event.IsMouseEvent() && (event.flags() & ui::EF_IS_SYNTHESIZED))
     return true;
   return false;
 }
 
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 // WindowEventDispatcher, public:
 
 WindowEventDispatcher::WindowEventDispatcher(WindowTreeHost* host)
     : host_(host),
-      touch_ids_down_(0),
       mouse_pressed_handler_(NULL),
       mouse_moved_handler_(NULL),
       event_dispatch_target_(NULL),
       old_dispatch_target_(NULL),
       synthesize_mouse_move_(false),
       move_hold_count_(0),
       dispatching_held_event_(nullptr),
       observer_manager_(this),
       transform_events_(true),
+      env_controller_(new EnvInputStateController),
       repost_event_factory_(this),
       held_event_factory_(this) {
   ui::GestureRecognizer::Get()->AddGestureEventHelper(this);
   Env::GetInstance()->AddObserver(this);
 }
 
 WindowEventDispatcher::~WindowEventDispatcher() {
   TRACE_EVENT0("shutdown", "WindowEventDispatcher::Destructor");
   Env::GetInstance()->RemoveObserver(this);
   ui::GestureRecognizer::Get()->RemoveGestureEventHelper(this);
@@ skipping 111 matching lines @@
   return location;
 }
 
 void WindowEventDispatcher::OnHostLostMouseGrab() {
   mouse_pressed_handler_ = NULL;
   mouse_moved_handler_ = NULL;
 }
 
 void WindowEventDispatcher::OnCursorMovedToRootLocation(
     const gfx::Point& root_location) {
-  SetLastMouseLocation(window(), root_location);
+  env_controller_->SetLastMouseLocation(window(), root_location);
 
   // Synthesize a mouse move in case the cursor's location in root coordinates
   // changed but its position in WindowTreeHost coordinates did not.
   PostSynthesizeMouseMove();
 }
 
 void WindowEventDispatcher::OnPostNotifiedWindowDestroying(Window* window) {
   OnWindowHidden(window, WINDOW_DESTROYED);
 }
 
@@ skipping 28 matching lines @@
       return;
   }
 }
 
 ui::EventDispatchDetails WindowEventDispatcher::DispatchMouseEnterOrExit(
     Window* target,
     const ui::MouseEvent& event,
     ui::EventType type) {
   if (event.type() != ui::ET_MOUSE_CAPTURE_CHANGED &&
       !(event.flags() & ui::EF_IS_SYNTHESIZED)) {
-    SetLastMouseLocation(window(), event.root_location());
+    env_controller_->SetLastMouseLocation(window(), event.root_location());
   }
 
   if (!mouse_moved_handler_ || !mouse_moved_handler_->delegate() ||
       !window()->Contains(mouse_moved_handler_))
     return DispatchDetails();
 
   // |event| may be an event in the process of being dispatched to a target (in
   // which case its locations will be in the event's target's coordinate
   // system), or a synthetic event created in root-window (in which case, the
   // event's target will be NULL, and the event will be in the root-window's
@@ skipping 462 matching lines @@
     Window* target,
     ui::LocatedEvent* event) {
   int flags = event->flags();
   if (IsNonClientLocation(target, event->location()))
     flags |= ui::EF_IS_NON_CLIENT;
   event->set_flags(flags);
 
   if (!is_dispatched_held_event(*event) &&
       (event->IsMouseEvent() || event->IsScrollEvent()) &&
       !(event->flags() & ui::EF_IS_SYNTHESIZED)) {
-    if (event->type() != ui::ET_MOUSE_CAPTURE_CHANGED)
-      SetLastMouseLocation(window(), event->root_location());
     synthesize_mouse_move_ = false;
   }
 
   return DispatchDetails();
 }
 
 DispatchDetails WindowEventDispatcher::PreDispatchMouseEvent(
     Window* target,
     ui::MouseEvent* event) {
   client::CursorClient* cursor_client = client::GetCursorClient(window());
   // We allow synthesized mouse exit events through even if mouse events are
   // disabled. This ensures that hover state, etc on controls like buttons is
   // cleared.
   if (cursor_client &&
       !cursor_client->IsMouseEventsEnabled() &&
       (event->flags() & ui::EF_IS_SYNTHESIZED) &&
       (event->type() != ui::ET_MOUSE_EXITED)) {
     event->SetHandled();
     return DispatchDetails();
   }
 
   if (IsEventCandidateForHold(*event) && !dispatching_held_event_) {
     if (move_hold_count_) {
-      if (!(event->flags() & ui::EF_IS_SYNTHESIZED) &&

[Mark Dittmer, 2016/06/08 15:31:30]

I do not yet understand why this is the case, but removing this code broke
WindowEventDispatcherTest.MouseMovesHeld. Adding it back (calling via
env_controller_) fixes the test.

[sadrul, 2016/06/08 17:07:27]

Perhaps we can move the call to
|env_controller_->UpdateStateForMouseEvent(window(), event);| before this, for
example, in line ~776.

[Mark Dittmer, 2016/06/09 15:17:10]

Not sure I quite understand. Are you advocating that we drop the three layers of
conditionals around |SetLastMouseLocation|? Line 776 appears to mean "here, but
outside the 3 if's".

[sadrul, 2016/06/09 15:21:40]

Yeah. The rest of the early returns seem to be related to destruction of a
window (or the dispatcher itself) on dispatching an enter/exit event, which
should probably still update the system mouse-location. So yeah, I would try
that out.

[Mark Dittmer, 2016/06/10 18:03:32]

Looks like no luck (see recent upload).
WindowEventDispatcherTest.SynthesizedLocatedEvent breaks, so the check for
EF_IS_SYNTHESIZED, at the least, is still necessary.

-          event->type() != ui::ET_MOUSE_CAPTURE_CHANGED) {
-        SetLastMouseLocation(window(), event->root_location());
-      }
       held_move_event_.reset(new ui::MouseEvent(*event, target, window()));
       event->SetHandled();
       return DispatchDetails();
     } else {
       // We may have a held event for a period between the time move_hold_count_
       // fell to 0 and the DispatchHeldEvents executes. Since we're going to
       // dispatch the new event directly below, we can reset the old one.
       held_move_event_.reset();
     }
   }
@@ skipping 51 matching lines @@
         }
       }
       break;
     case ui::ET_MOUSE_PRESSED:
       // Don't set the mouse pressed handler for non client mouse down events.
       // These are only sent by Windows and are not always followed with non
       // client mouse up events which causes subsequent mouse events to be
       // sent to the wrong target.
       if (!(event->flags() & ui::EF_IS_NON_CLIENT) && !mouse_pressed_handler_)
         mouse_pressed_handler_ = target;
-      Env::GetInstance()->set_mouse_button_flags(event->button_flags());
       break;
     case ui::ET_MOUSE_RELEASED:
       mouse_pressed_handler_ = NULL;
-      Env::GetInstance()->set_mouse_button_flags(
-          event->button_flags() & ~event->changed_button_flags());
       break;
     default:
       break;
   }
 
+  env_controller_->UpdateStateForMouseEvent(window(), event);
+
   return PreDispatchLocatedEvent(target, event);
 }
 
 DispatchDetails WindowEventDispatcher::PreDispatchTouchEvent(
     Window* target,
     ui::TouchEvent* event) {
-  switch (event->type()) {
-    case ui::ET_TOUCH_PRESSED:
-      touch_ids_down_ |= (1 << event->touch_id());
-      Env::GetInstance()->set_touch_down(touch_ids_down_ != 0);
-      break;
-
-      // Handle ET_TOUCH_CANCELLED only if it has a native event.
-    case ui::ET_TOUCH_CANCELLED:
-      if (!event->HasNativeEvent())
-        break;
-      // fallthrough
-    case ui::ET_TOUCH_RELEASED:
-      touch_ids_down_ = (touch_ids_down_ | (1 << event->touch_id())) ^
-            (1 << event->touch_id());
-      Env::GetInstance()->set_touch_down(touch_ids_down_ != 0);
-      break;
-
-    case ui::ET_TOUCH_MOVED:
-      if (move_hold_count_ && !dispatching_held_event_) {
+  if (event->type() == ui::ET_TOUCH_MOVED && move_hold_count_ &&
+      !dispatching_held_event_) {
         held_move_event_.reset(new ui::TouchEvent(*event, target, window()));
         event->SetHandled();
         return DispatchDetails();
-      }
-      break;
+  }
 
-    default:
-      NOTREACHED();
-      break;
-  }
+  env_controller_->UpdateStateForTouchEvent(event);
 
   ui::TouchEvent orig_event(*event, target, window());
   if (!ui::GestureRecognizer::Get()->ProcessTouchEventPreDispatch(&orig_event,
                                                                   target)) {
     // The event is invalid - ignore it.
     event->StopPropagation();
     event->DisableSynchronousHandling();
     return DispatchDetails();
   }
 
   // This flag is set depending on the gestures recognized in the call above,
   // and needs to propagate with the forwarded event.
   event->set_may_cause_scrolling(orig_event.may_cause_scrolling());
 
   return PreDispatchLocatedEvent(target, event);
 }
 
 }  // namespace aura