Improve initialization failure handling in VulkanInstance

In debug builds VulkanInstance::Destroy() was trying to call
vkDestroyDebugReportCallbackEXT and it would DCHECK after a failure to
find that function. That would happen even if Destroy() is called in
after a failed attempt to load Vulkan libs. It doesn't make sense to
DCHECK in that case. Also now vkDestroyDebugReportCallbackEXT() is
called only if debug callbacks were created successfully.

Bug: 861853
Change-Id: I03bbdbb1793ddb74f07352f354d0f70ee739a93a
Reviewed-on: https://chromium-review.googlesource.com/c/1332263
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607476}
1 file changed