Add initial support for creating a vulkan secondary command buffer drawing context.

This sets up the context and adds support for creating RTContexts, RTProxies, RTs,
and GrVkRenderPass's that wrap the external secondary command buffer.

Bug: skia:
Change-Id: I80ebbb690a5fe464f775c5fcad651dfe2a150418
Reviewed-on: https://skia-review.googlesource.com/c/178926
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/GrResourceProvider.cpp b/src/gpu/GrResourceProvider.cpp
index 1193246..6e821db 100644
--- a/src/gpu/GrResourceProvider.cpp
+++ b/src/gpu/GrResourceProvider.cpp
@@ -252,6 +252,14 @@
     return this->isAbandoned() ? nullptr : fGpu->wrapBackendRenderTarget(backendRT);
 }
 
+sk_sp<GrRenderTarget> GrResourceProvider::wrapVulkanSecondaryCBAsRenderTarget(
+        const SkImageInfo& imageInfo, const GrVkDrawableInfo& vkInfo) {
+    ASSERT_SINGLE_OWNER
+    return this->isAbandoned() ? nullptr : fGpu->wrapVulkanSecondaryCBAsRenderTarget(imageInfo,
+                                                                                     vkInfo);
+
+}
+
 void GrResourceProvider::assignUniqueKeyToResource(const GrUniqueKey& key,
                                                    GrGpuResource* resource) {
     ASSERT_SINGLE_OWNER