Implement --ozone-platform flag to select OzonePlatform implementation at runtime

ui/ozone/platform/test/ozone_platform_test.cc

 // Copyright 2013 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 "ui/ozone/platform/test/ozone_platform_test.h"
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "ui/ozone/ozone_platform.h"
 #include "ui/ozone/ozone_switches.h"
 
 namespace ui {
 
 OzonePlatformTest::OzonePlatformTest(const base::FilePath& dump_file)
     : surface_factory_ozone_(dump_file) {}
 
 OzonePlatformTest::~OzonePlatformTest() {}
 
 gfx::SurfaceFactoryOzone* OzonePlatformTest::GetSurfaceFactoryOzone() {
   return &surface_factory_ozone_;
 }
 
 ui::EventFactoryOzone* OzonePlatformTest::GetEventFactoryOzone() {
   return &event_factory_ozone_;
 }
 
-OzonePlatform* CreateDefaultOzonePlatform() {
+OzonePlatform* CreateOzonePlatformTest() {
   CommandLine* cmd = CommandLine::ForCurrentProcess();
   base::FilePath location = base::FilePath("/dev/null");
   if (cmd->HasSwitch(switches::kOzoneDumpFile))
     location = cmd->GetSwitchValuePath(switches::kOzoneDumpFile);
   return new OzonePlatformTest(location);
 }
 
 }  // namespace ui