ozone: Introduce ClientPixmap and ClientPixmapFactory for non-GPU processes.

ui/ozone/public/ozone_client.cc

+// 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 "base/command_line.h"
+#include "base/lazy_instance.h"
+#include "base/logging.h"
+#include "base/trace_event/trace_event.h"
+#include "ui/ozone/platform_object.h"
+#include "ui/ozone/platform_selection.h"
+#include "ui/ozone/public/ozone_client.h"
+#include "ui/ozone/public/ozone_platform.h"
+#include "ui/ozone/public/ozone_switches.h"
+
+namespace ui {
+
+namespace {
+
+OzoneClient* g_instance = nullptr;
+
+}  // namespace
+
+OzoneClient::OzoneClient() {
+  DCHECK(!g_instance) << "There should only be a single OzoneClient.";
+  g_instance = this;
+}
+
+OzoneClient::~OzoneClient() {
+  DCHECK_EQ(g_instance, this);
+  g_instance = nullptr;
+}
+
+// static
+void OzoneClient::InitializeForUI() {
+  if (g_instance)
+    return;
+
+  CreateInstance();
+  g_instance->InitializeUI();
+}
+
+// static
+void OzoneClient::InitializeForRenderer() {
+  if (g_instance)
+    return;
+
+  CreateInstance();
+  g_instance->InitializeRenderer();
+}
+
+// static
+OzoneClient* OzoneClient::GetInstance() {
+  DCHECK(g_instance) << "OzoneClient is not initialized";
+  return g_instance;
+}
+
+// static
+void OzoneClient::CreateInstance() {
+  if (!g_instance) {
+    TRACE_EVENT1("ozone", "OzoneClient::CreateInstance", "platform",
+                 GetOzonePlatformName());
+    scoped_ptr<OzoneClient> platform = PlatformObject<OzoneClient>::Create();
+
+    // TODO(spang): Currently need to leak this object.
+    OzoneClient* pl = platform.release();
+    DCHECK_EQ(g_instance, pl);
+  }
+}
+
+}  // namespace ui