Vulkan: Add CommandGraph class.

This also renames CommandBufferNode to CommandGraphNode. It also
renames some of the intenal members to more closely represent the
tree relationships (parents/children). This should clean up the
command graph classes and make them a bit easier to understand.

Bug: angleproject:2361
Change-Id: I024bffcc7f4157c78072ef902a3c40a07a08b18a
Reviewed-on: https://chromium-review.googlesource.com/922121
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/renderer/vulkan/TextureVk.cpp b/src/libANGLE/renderer/vulkan/TextureVk.cpp
index 130e92b..b8faf16 100644
--- a/src/libANGLE/renderer/vulkan/TextureVk.cpp
+++ b/src/libANGLE/renderer/vulkan/TextureVk.cpp
@@ -253,7 +253,7 @@
     stagingImage.getDeviceMemory().unmap(device);
 
     vk::CommandBuffer *commandBuffer = nullptr;
-    ANGLE_TRY(beginWriteOperation(renderer, &commandBuffer));
+    ANGLE_TRY(beginWriteResource(renderer, &commandBuffer));
 
     stagingImage.getImage().changeLayoutWithStages(
         VK_IMAGE_ASPECT_COLOR_BIT, VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL,