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

ui/aura/window_event_dispatcher.cc

Index: ui/aura/window_event_dispatcher.cc
diff --git a/ui/aura/window_event_dispatcher.cc b/ui/aura/window_event_dispatcher.cc
index 8b2228096f0cfd241ac23db11598536bfde9c161..90519746f9643e3fc1b06a3ffbb7d74168587684 100644
--- a/ui/aura/window_event_dispatcher.cc
+++ b/ui/aura/window_event_dispatcher.cc
@@ -19,6 +19,7 @@
 #include "ui/aura/env.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
+#include "ui/aura/window_event_dispatcher_delegate.h"
 #include "ui/aura/window_targeter.h"
 #include "ui/aura/window_tracker.h"
 #include "ui/aura/window_tree_host.h"
@@ -48,19 +49,6 @@ 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;
@@ -88,6 +76,7 @@ WindowEventDispatcher::WindowEventDispatcher(WindowTreeHost* host)
       dispatching_held_event_(nullptr),
       observer_manager_(this),
       transform_events_(true),
+      delegate_(new WindowEventDispatcherDelegate),
       repost_event_factory_(this),
       held_event_factory_(this) {
   ui::GestureRecognizer::Get()->AddGestureEventHelper(this);
@@ -204,12 +193,7 @@ void WindowEventDispatcher::ReleasePointerMoves() {
 }
 
 gfx::Point WindowEventDispatcher::GetLastMouseLocationInRoot() const {
-  gfx::Point location = Env::GetInstance()->last_mouse_location();
-  client::ScreenPositionClient* client =
-      client::GetScreenPositionClient(window());
-  if (client)
-    client->ConvertPointFromScreen(window(), &location);
-  return location;
+  return delegate_->GetLastMouseLocationInRoot(window());
 }
 
 void WindowEventDispatcher::OnHostLostMouseGrab() {
@@ -219,7 +203,7 @@ void WindowEventDispatcher::OnHostLostMouseGrab() {
 
 void WindowEventDispatcher::OnCursorMovedToRootLocation(
     const gfx::Point& root_location) {
-  SetLastMouseLocation(window(), root_location);
+  delegate_->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.
@@ -268,7 +252,7 @@ ui::EventDispatchDetails WindowEventDispatcher::DispatchMouseEnterOrExit(
     ui::EventType type) {
   if (event.type() != ui::ET_MOUSE_CAPTURE_CHANGED &&
       !(event.flags() & ui::EF_IS_SYNTHESIZED)) {
-    SetLastMouseLocation(window(), event.root_location());
+    delegate_->SetLastMouseLocation(window(), event.root_location());
   }
 
   if (!mouse_moved_handler_ || !mouse_moved_handler_->delegate() ||
@@ -387,7 +371,7 @@ void WindowEventDispatcher::UpdateCapture(Window* old_capture,
   if (new_capture) {
     // Make all subsequent mouse events go to the capture window. We shouldn't
     // need to send an event here as OnCaptureLost() should take care of that.
-    if (mouse_moved_handler_ || Env::GetInstance()->IsMouseButtonDown())
+    if (mouse_moved_handler_ || delegate_->IsMouseButtonDown())
       mouse_moved_handler_ = new_capture;
   } else {
     // Make sure mouse_moved_handler gets updated.
@@ -726,7 +710,7 @@ ui::EventDispatchDetails WindowEventDispatcher::SynthesizeMouseMoveEvent() {
   // instead of a MOVED event, but in multi-display/multi-host scenarios, the
   // DRAGGED event can be synthesized in the incorrect host. So avoid
   // synthesizing any events at all.
-  if (Env::GetInstance()->mouse_button_flags())
+  if (delegate_->IsMouseButtonDown())
     return details;
 
   gfx::Point root_mouse_location = GetLastMouseLocationInRoot();
@@ -752,7 +736,7 @@ DispatchDetails WindowEventDispatcher::PreDispatchLocatedEvent(
       (event->IsMouseEvent() || event->IsScrollEvent()) &&
       !(event->flags() & ui::EF_IS_SYNTHESIZED)) {
     if (event->type() != ui::ET_MOUSE_CAPTURE_CHANGED)
-      SetLastMouseLocation(window(), event->root_location());
+      delegate_->SetLastMouseLocation(window(), event->root_location());
     synthesize_mouse_move_ = false;
   }
 
@@ -778,7 +762,7 @@ DispatchDetails WindowEventDispatcher::PreDispatchMouseEvent(
     if (move_hold_count_) {
       if (!(event->flags() & ui::EF_IS_SYNTHESIZED) &&
           event->type() != ui::ET_MOUSE_CAPTURE_CHANGED) {
-        SetLastMouseLocation(window(), event->root_location());
+        delegate_->SetLastMouseLocation(window(), event->root_location());
       }
       held_move_event_.reset(new ui::MouseEvent(*event, target, window()));
       event->SetHandled();
@@ -851,17 +835,16 @@ DispatchDetails WindowEventDispatcher::PreDispatchMouseEvent(
       // 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;
   }
 
+  delegate_->PreDispatchMouseEvent(event);
+
   return PreDispatchLocatedEvent(target, event);
 }
 
@@ -871,7 +854,6 @@ DispatchDetails WindowEventDispatcher::PreDispatchTouchEvent(
   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.
@@ -882,7 +864,6 @@ DispatchDetails WindowEventDispatcher::PreDispatchTouchEvent(
     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:
@@ -898,6 +879,8 @@ DispatchDetails WindowEventDispatcher::PreDispatchTouchEvent(
       break;
   }
 
+  delegate_->PreDispatchTouchEvent(event, touch_ids_down_);
+
   ui::TouchEvent orig_event(*event, target, window());
   if (!ui::GestureRecognizer::Get()->ProcessTouchEventPreDispatch(&orig_event,
                                                                   target)) {