mus: Use the new drag API to implement tab dragging in chrome.

ui/views/mus/native_widget_mus.cc

Index: ui/views/mus/native_widget_mus.cc
diff --git a/ui/views/mus/native_widget_mus.cc b/ui/views/mus/native_widget_mus.cc
index 9bed4cca17d179f1dc34a82c230db8139edd6ec4..2c3fec31e461380f6fb6676645c5557eac7b1bad 100644
--- a/ui/views/mus/native_widget_mus.cc
+++ b/ui/views/mus/native_widget_mus.cc
@@ -7,6 +7,7 @@
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/bitmap_uploader/bitmap_uploader.h"
 #include "components/mus/public/cpp/property_type_converters.h"
@@ -29,6 +30,7 @@
 #include "ui/base/view_prop.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
+#include "ui/display/screen.h"
 #include "ui/events/event.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/path.h"
@@ -328,7 +330,7 @@ SkBitmap AppIconFromDelegate(WidgetDelegate* delegate) {
   return app_icon.GetRepresentation(1.f).sk_bitmap();
 }
 
-// Handles acknowledgement of an input event, either immediately when a nested
+// Handles acknowledgment of an input event, either immediately when a nested
 // message loop starts, or upon destruction.
 class EventAckHandler : public base::MessageLoop::NestingObserver {
  public:
@@ -366,6 +368,13 @@ class EventAckHandler : public base::MessageLoop::NestingObserver {
   DISALLOW_COPY_AND_ASSIGN(EventAckHandler);
 };
 
+void OnMoveLoopEnd(bool* out_success,
+                   base::Closure quit_closure,
+                   bool in_success) {
+  *out_success = in_success;
+  quit_closure.Run();
+}
+
 }  // namespace
 
 class NativeWidgetMus::MusWindowObserver : public mus::WindowObserver {
@@ -438,6 +447,13 @@ class NativeWidgetMus::MusWindowObserver : public mus::WindowObserver {
     DCHECK_EQ(window, mus_window());
     window_tree_host()->SetBounds(new_bounds);
   }
+  void OnWindowBoundsChanged(mus::Window* window,
+                             const gfx::Rect& old_bounds,
+                             const gfx::Rect& new_bounds) override {
+    Widget* widget = NativeWidgetMus::GetWidgetForWindow(window);

[sky, 2016/06/30 00:18:31]

How come NativeWidgetMus::OnBoundsChanged doesn't cover this?

[Elliot Glaysher, 2016/06/30 19:48:25]

Because it doesn't get called in response to this. (And shouldn't.)

During MusWindowObserver::OnWindowBoundsChanging(), we tell
WindowTreeHostPlatform::SetBounds() the new bounds. That goes to
StubWindow::SetBounds(). That goes to WindowTreeHostPlatform::OnBoundsChanged(),
which dispatchs to aura::WindowTreeHostObserver.

However, pulling on this thread, this chunk is still wrong. I've replaced this
with making NWMus implement aura::WTHO. Looking at DesktopNativeWidgetAura, we
should have a OnHostMoved() method calling Widget::OnNativeWidgetMove() instead.

+    if (widget)
+      widget->OnNativeWidgetMove();
+  }
   void OnWindowFocusChanged(mus::Window* gained_focus,
                             mus::Window* lost_focus) override {
     if (gained_focus == mus_window())
@@ -804,14 +820,14 @@ void NativeWidgetMus::ViewRemoved(View* view) {
 // used safely in a world where we separate things with mojo. They should be
 // removed; not ported.
 void NativeWidgetMus::SetNativeWindowProperty(const char* name, void* value) {
-  // TODO(beng): push properties to mus::Window.
-  // NOTIMPLEMENTED();
+  native_window_properties_[name] = value;
 }
 
 void* NativeWidgetMus::GetNativeWindowProperty(const char* name) const {
-  // TODO(beng): pull properties to mus::Window.
-  // NOTIMPLEMENTED();
-  return nullptr;
+  auto it = native_window_properties_.find(name);
+  if (it == native_window_properties_.end())
+    return nullptr;
+  return it->second;
 }
 
 TooltipManager* NativeWidgetMus::GetTooltipManager() const {
@@ -1166,12 +1182,31 @@ Widget::MoveLoopResult NativeWidgetMus::RunMoveLoop(
     const gfx::Vector2d& drag_offset,
     Widget::MoveLoopSource source,
     Widget::MoveLoopEscapeBehavior escape_behavior) {
-  // NOTIMPLEMENTED();
-  return Widget::MOVE_LOOP_CANCELED;
+  ReleaseCapture();
+
+  base::MessageLoopForUI* loop = base::MessageLoopForUI::current();
+  base::MessageLoop::ScopedNestableTaskAllower allow_nested(loop);
+  base::RunLoop run_loop;
+
+  mus::mojom::MoveLoopSource mus_source =
+      source == Widget::MOVE_LOOP_SOURCE_MOUSE ?
+      mus::mojom::MoveLoopSource::MOUSE :
+      mus::mojom::MoveLoopSource::TOUCH;
+
+  bool success = false;
+  gfx::Point cursor_location =
+      display::Screen::GetScreen()->GetCursorScreenPoint();
+  window_->PerformWindowMove(
+      mus_source, cursor_location,
+      base::Bind(OnMoveLoopEnd, &success, run_loop.QuitClosure()));
+
+  run_loop.Run();
+
+  return success ? Widget::MOVE_LOOP_SUCCESSFUL : Widget::MOVE_LOOP_CANCELED;
 }
 
 void NativeWidgetMus::EndMoveLoop() {
-  // NOTIMPLEMENTED();
+  window_->CancelWindowMove();
 }
 
 void NativeWidgetMus::SetVisibilityChangedAnimationsEnabled(bool value) {