Add ability to relinquish control of VkDevice and VkInstance lifetime to GrVkBackendContext

Change-Id: I355a8bf573a84b4ba7cbfeed60feec13e251b352
Reviewed-on: https://skia-review.googlesource.com/14303
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

1 files changed, 18 insertions, 5 deletions

diff --git a/include/gpu/vk/GrVkBackendContext.h b/include/gpu/vk/GrVkBackendContext.h
index 5838caa323..987b32f3b3 100644
--- a/include/gpu/vk/GrVkBackendContext.h
+++ b/include/gpu/vk/GrVkBackendContext.h
@@ -45,15 +45,28 @@ struct GrVkBackendContext : public SkRefCnt {
     uint32_t                   fExtensions;
     uint32_t                   fFeatures;
     sk_sp<const GrVkInterface> fInterface;
+    /**
+     * Controls whether this object destroys the instance and device upon destruction. The default
+     * is temporarily 'true' to avoid breaking existing clients but will be changed to 'false'.
+     */
+    bool                       fOwnsInstanceAndDevice = true;
 
     using CanPresentFn = std::function<bool(VkInstance, VkPhysicalDevice,
                                             uint32_t queueFamilyIndex)>;
 
-    // Helper function to create the default Vulkan objects needed by the GrVkGpu object
-    // If getProc is NULL, a default getProc will be constructed if we are statically linking
-    // against Vulkan.
-    // If presentQueueIndex is non-NULL, will try to set up presentQueue as part of device
-    // creation using the platform-specific canPresent() function.
+    /**
+     * Helper function to create the Vulkan objects needed for a Vulkan-backed GrContext.
+     * If getProc is null, a default getProc will be constructed if we are statically linking
+     * against Vulkan. Note that this default behavior will be removed soon as well as the version
+     * that uses the unified "GetProc" instead of separate "GetInstanceProc" and "GetDeviceProc"
+     * functions.
+     *
+     * If presentQueueIndex is non-NULL, will try to set up presentQueue as part of device
+     * creation using the platform-specific canPresent() function.
+     *
+     * This will set fOwnsInstanceAndDevice to 'true'. If it is subsequently set to 'false' then
+     * the client owns the lifetime of the created VkDevice and VkInstance.
+     */
     static const GrVkBackendContext* Create(uint32_t* presentQueueIndex = nullptr,
                                             CanPresentFn = CanPresentFn(),
                                             GrVkInterface::GetProc getProc = nullptr);