Adds capture to the mojo window_manager.

services/window_manager/capture_controller.cc

Index: services/window_manager/capture_controller.cc
diff --git a/services/window_manager/capture_controller.cc b/services/window_manager/capture_controller.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a3743ee99f84820ba7e180330e3ffba973edf713
--- /dev/null
+++ b/services/window_manager/capture_controller.cc
@@ -0,0 +1,105 @@
+// 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 "services/window_manager/capture_controller.h"
+
+#include "mojo/services/view_manager/public/cpp/view_property.h"
+#include "mojo/services/view_manager/public/cpp/view_tracker.h"
+#include "services/window_manager/capture_controller_observer.h"
+
+DECLARE_VIEW_PROPERTY_TYPE(window_manager::CaptureController*);
+
+namespace window_manager {
+
+namespace {
+DEFINE_VIEW_PROPERTY_KEY(CaptureController*,
+                         kRootViewCaptureController,
+                         nullptr);
+}  // namespace
+
+CaptureController::CaptureController()
+    : capture_view_(nullptr) {}
+
+CaptureController::~CaptureController() {}
+
+void CaptureController::AddObserver(CaptureControllerObserver* observer) {
+  capture_controller_observers_.AddObserver(observer);
+}
+
+void CaptureController::RemoveObserver(CaptureControllerObserver* observer) {
+  capture_controller_observers_.RemoveObserver(observer);
+}
+
+void CaptureController::SetCapture(mojo::View* view) {
+  if (capture_view_ == view)
+    return;
+
+  if (capture_view_)
+    capture_view_->RemoveObserver(this);
+
+  mojo::View* old_capture_view = capture_view_;
+  capture_view_ = view;
+
+  if (capture_view_)
+    capture_view_->AddObserver(this);
+
+  NotifyCaptureChange(old_capture_view, capture_view_);
+}
+
+void CaptureController::ReleaseCapture(mojo::View* view) {
+  if (capture_view_ != view)
+    return;
+  SetCapture(nullptr);
+}
+
+mojo::View* CaptureController::GetCapture() {
+  return capture_view_;
+}
+
+void CaptureController::NotifyCaptureChange(mojo::View* old_capture,

[sky, 2014/12/16 03:44:19]

How about swapping order so it's consistant with OnCaptureChanged. That said, I
actually prefer this ordering (old, new). But it should match the observer
function, so swap that one too.

+                                            mojo::View* new_capture) {
+  mojo::ViewTracker view_tracker;
+  if (old_capture)
+    view_tracker.Add(old_capture);
+  if (new_capture)
+    view_tracker.Add(new_capture);
+
+  FOR_EACH_OBSERVER(
+      CaptureControllerObserver,
+      capture_controller_observers_,
+      OnCaptureChanged(
+          view_tracker.Contains(new_capture) ? new_capture : nullptr,
+          view_tracker.Contains(old_capture) ? old_capture : nullptr));
+}
+
+void CaptureController::OnViewDestroying(mojo::View* view) {
+  if (view == capture_view_) {
+    view->RemoveObserver(this);
+    NotifyCaptureChange(view, nullptr);
+    capture_view_ = nullptr;
+  }
+}
+
+void SetCaptureController(mojo::View* root_view,
+                          CaptureController* capture_controller) {
+  DCHECK_EQ(root_view->GetRoot(), root_view);
+  root_view->SetLocalProperty(kRootViewCaptureController, capture_controller);
+}
+
+CaptureController* GetCaptureController(mojo::View* root_view) {
+  if (root_view)
+    DCHECK_EQ(root_view->GetRoot(), root_view);
+  return root_view ?
+      root_view->GetLocalProperty(kRootViewCaptureController) : nullptr;
+}
+
+mojo::View* GetCaptureView(mojo::View* view) {
+  mojo::View* root = view->GetRoot();
+  if (!root)
+    return nullptr;
+  CaptureController* controller = GetCaptureController(root);
+  return controller ? controller->GetCapture() : nullptr;
+}
+
+}  // namespace window_manager