Convert Skia calls to use SkColorType/BackendFormats instead of GrPixelConfig.

Test: manual testing

Change-Id: I645bcea55f49292309cf0bb5de21891bb5b62dda
diff --git a/libs/hwui/renderthread/VulkanManager.cpp b/libs/hwui/renderthread/VulkanManager.cpp
index 21c91a2..ffe0578 100644
--- a/libs/hwui/renderthread/VulkanManager.cpp
+++ b/libs/hwui/renderthread/VulkanManager.cpp
@@ -320,7 +320,8 @@
 
         VulkanSurface::ImageInfo& imageInfo = surface->mImageInfos[i];
         imageInfo.mSurface = SkSurface::MakeFromBackendRenderTarget(
-                mRenderThread.getGrContext(), backendRT, kTopLeft_GrSurfaceOrigin, nullptr, &props);
+                mRenderThread.getGrContext(), backendRT, kTopLeft_GrSurfaceOrigin,
+                kRGBA_8888_SkColorType, nullptr, &props);
     }
 
     SkASSERT(mCommandPool != VK_NULL_HANDLE);