Have the framework setup android defines for including vulkan.h

We're moving skia to place where it has its own vulkan header and
the clients have theirs. So this sets up the VulkanManager to be
able to handle including vulkan.h how it wants to.

Test: manual building and running

Change-Id: I0818d2fc607bf8a265bf6ddf1e2f737d1228131a
diff --git a/libs/hwui/renderthread/VulkanManager.h b/libs/hwui/renderthread/VulkanManager.h
index 9a72706..69641d5 100644
--- a/libs/hwui/renderthread/VulkanManager.h
+++ b/libs/hwui/renderthread/VulkanManager.h
@@ -17,11 +17,14 @@
 #ifndef VULKANMANAGER_H
 #define VULKANMANAGER_H
 
+#if !defined(VK_USE_PLATFORM_ANDROID_KHR)
+#  define VK_USE_PLATFORM_ANDROID_KHR
+#endif
+#include <vulkan/vulkan.h>
+
 #include <SkSurface.h>
 #include <vk/GrVkBackendContext.h>
 
-#include <vulkan/vulkan.h>
-
 namespace android {
 namespace uirenderer {
 namespace renderthread {