ui: Allow individual test suites to opt-out of the TestCompositor.

ui/compositor/test/context_factories_for_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/compositor/test/context_factories_for_test.h"
 
 #include "base/command_line.h"
 #include "base/sys_info.h"
 #include "ui/compositor/compositor.h"
 #include "ui/compositor/compositor_switches.h"
 #include "ui/compositor/test/in_process_context_factory.h"
 #include "ui/compositor/test/test_context_factory.h"
 #include "ui/gl/gl_implementation.h"
 
+namespace {
+
+static ui::ContextFactory* g_implicit_factory = NULL;
+static gfx::DisableNullDrawGLBindings* g_disable_null_draw = NULL;
+
+}  // namespace
+
 namespace ui {
 
-static ContextFactory* g_implicit_factory = NULL;
-
 // static
 void InitializeContextFactoryForTests(bool enable_pixel_output) {
   DCHECK(!g_implicit_factory) <<
       "ContextFactory for tests already initialized.";
+  CommandLine* command_line = CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kEnablePixelOutputInTests))
+    enable_pixel_output = true;
 
   bool use_test_contexts = true;
 
+  if (gfx::HasInitializedNullDrawGLBindings())
+    use_test_contexts = false;
+
   // Always use test contexts unless the disable command line flag is used.
-  CommandLine* command_line = CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kDisableTestCompositor))
     use_test_contexts = false;
 
 #if defined(OS_CHROMEOS)
   // If the test is running on the chromeos envrionment (such as
   // device or vm bots), always use real contexts.
   if (base::SysInfo::IsRunningOnChromeOS())
     use_test_contexts = false;
 #endif
 
   if (enable_pixel_output)
     use_test_contexts = false;
 
   if (use_test_contexts) {
     g_implicit_factory = new ui::TestContextFactory;
   } else {
     DCHECK_NE(gfx::kGLImplementationNone, gfx::GetGLImplementation());
     DVLOG(1) << "Using InProcessContextFactory";
+    if (enable_pixel_output && gfx::HasInitializedNullDrawGLBindings())
+      g_disable_null_draw = new gfx::DisableNullDrawGLBindings;
     g_implicit_factory = new ui::InProcessContextFactory();
   }
   ContextFactory::SetInstance(g_implicit_factory);
 }
 
 void TerminateContextFactoryForTests() {
   ContextFactory::SetInstance(NULL);
   delete g_implicit_factory;
   g_implicit_factory = NULL;
+  delete g_disable_null_draw;
+  g_disable_null_draw = NULL;
 }
 
 }  // namespace ui