Reland: Use the real mouse position when synthesizing mouse events.

Aura synthesizes a mouse event at certain times, including when the
window comes back from being minimized. Currently it uses the last known
mouse position, which works in most cases. However, the window doesn't
get mouse events when minimized, so the last known position isn't
updated. When the window comes back, if the user's mouse is not over the
window it can cause buttons to get stuck in the hovered state until the
user moves the mouse back into the window.

To fix this, this patch uses the real mouse position.

This patch also updates content_shell to move the mouse to 0,0 in
headless mode, to avoid any queries to the real mouse position from
interfering with blink tests. This patch also adds an implementation
for MoveCursorTo on Windows.

Bug: 828591, 834166
Change-Id: I81354c77805c1928eb0cbccb900856a8c523709d
Reviewed-on: https://chromium-review.googlesource.com/1022959Reviewed-by: Mike West <mkwst@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555843}

content/shell/browser/shell_views.cc

@@ -444,6 +444,9 @@ void Shell::PlatformSetContents() {
     aura::Window* parent = platform_->host()->window();
     if (!parent->Contains(content)) {
       parent->AddChild(content);
+      // Move the cursor to a fixed position before tests run to avoid getting
+      // an unpredictable result from mouse events.
+      content->MoveCursorTo(gfx::Point());
       content->Show();
     }
     content->SetBounds(gfx::Rect(content_size_));

ui/aura/window_event_dispatcher.cc

@@ -28,6 +28,7 @@
 #include "ui/base/hit_test.h"
 #include "ui/base/ime/input_method.h"
 #include "ui/compositor/dip_util.h"
+#include "ui/display/screen.h"
 #include "ui/events/event.h"
 #include "ui/events/event_utils.h"
 #include "ui/events/gestures/gesture_recognizer.h"
@@ -227,10 +228,7 @@ 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);
+  ConvertPointFromScreen(&location);
   return location;
 }
 
@@ -264,6 +262,13 @@ const Window* WindowEventDispatcher::window() const {
   return host_->window();
 }
 
+void WindowEventDispatcher::ConvertPointFromScreen(gfx::Point* point) const {
+  client::ScreenPositionClient* client =
+      client::GetScreenPositionClient(window());
+  if (client)
+    client->ConvertPointFromScreen(window(), point);
+}
+
 void WindowEventDispatcher::TransformEventForDeviceScaleFactor(
     ui::LocatedEvent* event) {
   event->UpdateForRootTransform(
@@ -860,10 +865,14 @@ ui::EventDispatchDetails WindowEventDispatcher::SynthesizeMouseMoveEvent() {
   if (Env::GetInstance()->mouse_button_flags())
     return details;
 
-  gfx::Point root_mouse_location = GetLastMouseLocationInRoot();
-  if (!window()->bounds().Contains(root_mouse_location))
+  // Do not use GetLastMouseLocationInRoot here because it's not updated when
+  // the mouse is not over the window or when the window is minimized.
+  gfx::Point mouse_location =
+      display::Screen::GetScreen()->GetCursorScreenPoint();
+  ConvertPointFromScreen(&mouse_location);
+  if (!window()->bounds().Contains(mouse_location))
     return details;
-  gfx::Point host_mouse_location = root_mouse_location;
+  gfx::Point host_mouse_location = mouse_location;
   host_->ConvertDIPToPixels(&host_mouse_location);
   ui::MouseEvent event(ui::ET_MOUSE_MOVED, host_mouse_location,
                        host_mouse_location, ui::EventTimeForNow(),

ui/aura/window_event_dispatcher.h

@@ -147,6 +147,10 @@ class AURA_EXPORT WindowEventDispatcher : public ui::EventProcessor,
   Window* window();
   const Window* window() const;
 
+  // Converts a point from screen coordinates to the coordinate space used by
+  // the Window returned from window().
+  void ConvertPointFromScreen(gfx::Point* screen_point) const;
+
   // Updates the event with the appropriate transform for the device scale
   // factor. The WindowEventDispatcher dispatches events in the physical pixel
   // coordinate. But the event processing from WindowEventDispatcher onwards

ui/platform_window/win/win_window.cc

@@ -125,7 +125,9 @@ void WinWindow::SetCursor(PlatformCursor cursor) {
   ::SetCursor(cursor);
 }
 
-void WinWindow::MoveCursorTo(const gfx::Point& location) {}
+void WinWindow::MoveCursorTo(const gfx::Point& location) {
+  ::SetCursorPos(location.x(), location.y());
+}
 
 void WinWindow::ConfineCursorToBounds(const gfx::Rect& bounds) {
 }