exo: Add support for subcompositor interface.

components/exo/sub_surface.cc

Index: components/exo/sub_surface.cc
diff --git a/components/exo/sub_surface.cc b/components/exo/sub_surface.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6cdca0705ddee7376d39edad3dc49abf0efb4c5b
--- /dev/null
+++ b/components/exo/sub_surface.cc
@@ -0,0 +1,126 @@
+// Copyright 2015 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 "components/exo/sub_surface.h"
+
+#include "base/logging.h"
+#include "base/trace_event/trace_event.h"
+#include "base/trace_event/trace_event_argument.h"
+#include "components/exo/surface.h"
+
+namespace exo {
+
+////////////////////////////////////////////////////////////////////////////////
+// SubSurface, public:
+
+SubSurface::SubSurface(Surface* surface, Surface* parent)
+    : surface_(surface), parent_(parent), is_synchronized_(true) {
+  surface_->SetSurfaceDelegate(this);
+  surface_->AddSurfaceObserver(this);
+  parent_->AddSurfaceObserver(this);
+  parent_->AddSubSurface(surface_);
+}
+
+SubSurface::~SubSurface() {
+  if (surface_) {
+    if (parent_)
+      parent_->RemoveSubSurface(surface_);
+    surface_->SetSurfaceDelegate(nullptr);
+    surface_->RemoveSurfaceObserver(this);
+  }
+  if (parent_)
+    parent_->RemoveSurfaceObserver(this);
+}
+
+void SubSurface::SetPosition(const gfx::Point& position) {
+  TRACE_EVENT1("exo", "SubSurface::SetPosition", "position",
+               position.ToString());
+
+  if (!parent_ || !surface_)
+    return;
+
+  parent_->SetSubSurfacePosition(surface_, position);
+}
+
+void SubSurface::PlaceAbove(Surface* reference) {
+  TRACE_EVENT1("exo", "SubSurface::PlaceAbove", "reference",
+               reference->AsTracedValue());
+
+  if (!parent_ || !surface_)
+    return;
+
+  if (reference == surface_) {
+    DLOG(WARNING) << "Client tried to place sub-surface above itself";
+    return;
+  }
+
+  parent_->PlaceSubSurfaceAbove(surface_, reference);
+}
+
+void SubSurface::PlaceBelow(Surface* sibling) {
+  TRACE_EVENT1("exo", "SubSurface::PlaceBelow", "sibling",
+               sibling->AsTracedValue());
+
+  if (!parent_ || !surface_)
+    return;
+
+  if (sibling == surface_) {
+    DLOG(WARNING) << "Client tried to place sub-surface below itself";
+    return;
+  }
+
+  parent_->PlaceSubSurfaceBelow(surface_, sibling);
+}
+
+void SubSurface::SetCommitBehavior(bool synchronized) {
+  TRACE_EVENT1("exo", "SubSurface::SetCommitBehavior", "synchronized",
+               synchronized);
+
+  is_synchronized_ = synchronized;
+}
+
+scoped_refptr<base::trace_event::TracedValue> SubSurface::AsTracedValue()
+    const {
+  scoped_refptr<base::trace_event::TracedValue> value =
+      new base::trace_event::TracedValue;
+  value->SetBoolean("is_synchronized", is_synchronized_);
+  return value;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// SurfaceDelegate overrides:
+
+void SubSurface::OnSurfaceCommit() {
+  // Early out if commit should be synchronized with parent.
+  if (IsSurfaceSynchronized())
+    return;
+
+  surface_->CommitSurfaceHierarchy();
+}
+
+bool SubSurface::IsSurfaceSynchronized() const {
+  // A sub-surface is effectively synchronized if either its parent is
+  // synchronized or itself is in synchronized mode.
+  if (is_synchronized_)
+    return true;
+
+  return parent_ ? parent_->IsSynchronized() : false;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// SurfaceObserver overrides:
+
+void SubSurface::OnSurfaceDestroying(Surface* surface) {
+  surface->RemoveSurfaceObserver(this);
+  if (surface == parent_) {
+    parent_ = nullptr;
+    return;
+  }
+  DCHECK(surface == surface_);
+  if (parent_)
+    parent_->RemoveSubSurface(surface_);
+  surface_ = nullptr;
+}
+
+}  // namespace exo