Added the Vulkan Context Provider implementation.

gpu/vulkan/vulkan_implementation.cc

 // Copyright (c) 2016 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 "gpu/vulkan/vulkan_implementation.h"
 
 #include <unordered_set>
 #include <vector>
 #include "base/logging.h"
 #include "base/macros.h"
@@ skipping 166 matching lines @@
 
 static VulkanInstance* vulkan_instance = nullptr;
 
 bool InitializeVulkan() {
   DCHECK(!vulkan_instance);
   vulkan_instance = new VulkanInstance;
   vulkan_instance->Initialize();
   return vulkan_instance->valid;
 }
 
+bool VulkanSupported() {
+  DCHECK(vulkan_instance);
+  return vulkan_instance->valid;
+}
+
 VkInstance GetVulkanInstance() {
   DCHECK(vulkan_instance);
   DCHECK(vulkan_instance->valid);
   return vulkan_instance->vk_instance;
 }
 
 }  // namespace gpu