ozone: Initialize a subsystem only if necessary.

ui/ozone/platform/test/ozone_platform_test.cc

Index: ui/ozone/platform/test/ozone_platform_test.cc
diff --git a/ui/ozone/platform/test/ozone_platform_test.cc b/ui/ozone/platform/test/ozone_platform_test.cc
index da94ba4b3f7e1ab18de5dbd0036183b8e2451fc7..eadfed484dd4ebcb235f64e9e40ed1a67db0873b 100644
--- a/ui/ozone/platform/test/ozone_platform_test.cc
+++ b/ui/ozone/platform/test/ozone_platform_test.cc
@@ -64,7 +64,7 @@ class OzonePlatformTest : public OzonePlatform {
 
 }  // namespace
 
-OzonePlatform* CreateOzonePlatformTest() {
+OzonePlatform* CreateOzonePlatformTestForUI() {
   CommandLine* cmd = CommandLine::ForCurrentProcess();
   base::FilePath location = base::FilePath("/dev/null");
   if (cmd->HasSwitch(switches::kOzoneDumpFile))
@@ -72,4 +72,8 @@ OzonePlatform* CreateOzonePlatformTest() {
   return new OzonePlatformTest(location);
 }
 
+OzonePlatform* CreateOzonePlatformTestForGPU() {
+  return NULL;
+}
+
 }  // namespace ui