Add WSI functions to GrVkInterface

include/gpu/vk/GrVkBackendContext.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrVkBackendContext_DEFINED
 #define GrVkBackendContext_DEFINED
 
 #include "SkRefCnt.h"
 
-#include "vulkan/vulkan.h"
+#include "vk/GrVkDefines.h"
 
 #ifdef SK_DEBUG
 #define ENABLE_VK_LAYERS
 #endif
 
 struct GrVkInterface;
 
 enum GrVkExtensionFlags {
-    kEXT_debug_report_GrVkExtensionFlag = 0x0001,
-    kNV_glsl_shader_GrVkExtensionFlag   = 0x0002,
+    kEXT_debug_report_GrVkExtensionFlag    = 0x0001,

[bsalomon, 2016/03/28 13:05:47]

Does this mix interface and device extensions? Do we care about separating them?
Same for features.

[jvanverth1, 2016/03/28 13:35:38]

The extensions are specified in docs just like OpenGL, with unique names. It's
just that you may need to enable them either on the interface or the device, or
both. So for this I don't think we care. Features are only a property of the
physical device.

+    kNV_glsl_shader_GrVkExtensionFlag      = 0x0002,
+    kKHR_surface_GrVkExtensionFlag         = 0x0004,
+    kKHR_swapchain_GrVkExtensionFlag       = 0x0008,
+    kKHR_win32_surface_GrVkExtensionFlag   = 0x0010,
+    kKHR_android_surface_GrVkExtensionFlag = 0x0020,
+    kKHR_xlib_surface_GrVkExtensionFlag    = 0x0040,
 };
 
 enum GrVkFeatureFlags {
     kGeometryShader_GrVkFeatureFlag    = 0x0001,
     kDualSrcBlend_GrVkFeatureFlag      = 0x0002,
     kSampleRateShading_GrVkFeatureFlag = 0x0004,
 };
 
 // The BackendContext contains all of the base Vulkan objects needed by the GrVkGpu. The assumption
 // is that the client will set these up and pass them to the GrVkGpu constructor. The VkDevice
@@ skipping 12 matching lines @@
     uint32_t                          fFeatures;
     SkAutoTUnref<const GrVkInterface> fInterface;
 
     // Helper function to create the default Vulkan objects needed by the GrVkGpu object
     static const GrVkBackendContext* Create();
 
     ~GrVkBackendContext() override;
 };
 
 #endif