Vulkan: Introduce vk::Format.

BUG=angleproject:1319

Change-Id: I88bcc6caa5d29565728848bada1563e47e383b29
Reviewed-on: https://chromium-review.googlesource.com/367753
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/renderer/renderer_utils.h b/src/libANGLE/renderer/renderer_utils.h
index 440548e..803c8c2 100644
--- a/src/libANGLE/renderer/renderer_utils.h
+++ b/src/libANGLE/renderer/renderer_utils.h
@@ -95,6 +95,13 @@
 ColorCopyFunction GetFastCopyFunction(const FastCopyFunctionMap &fastCopyFunctions,
                                       const gl::FormatType &formatType);
 
+using InitializeTextureDataFunction = void (*)(size_t width,
+                                               size_t height,
+                                               size_t depth,
+                                               uint8_t *output,
+                                               size_t outputRowPitch,
+                                               size_t outputDepthPitch);
+
 using LoadImageFunction = void (*)(size_t width,
                                    size_t height,
                                    size_t depth,