Vulkan: Rename PipelineDesc/Cache to Graphics&

PipelineDesc describes a Vertex-Fragment pipeline and PipelineCache (not
to be confused with vk::PipelineCache) implements a cache of such
pipeline objects.

In preparation for Compute support, these data structures are prefixed
with Graphics.

Bug: angleproject:2959
Change-Id: I9181586fb946b787216ca0b2ad6340f90c3ab55f
Reviewed-on: https://chromium-review.googlesource.com/c/1333971
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
diff --git a/src/libANGLE/renderer/vulkan/FramebufferVk.cpp b/src/libANGLE/renderer/vulkan/FramebufferVk.cpp
index e230ad2..771bd7e 100644
--- a/src/libANGLE/renderer/vulkan/FramebufferVk.cpp
+++ b/src/libANGLE/renderer/vulkan/FramebufferVk.cpp
@@ -1043,7 +1043,7 @@
     bool invertViewport             = contextVk->isViewportFlipEnabledForDrawFBO();
 
     // This pipeline desc could be cached.
-    vk::PipelineDesc pipelineDesc;
+    vk::GraphicsPipelineDesc pipelineDesc;
     pipelineDesc.initDefaults();
     pipelineDesc.updateColorWriteMask(colorMaskFlags, getEmulatedAlphaAttachmentMask());
     pipelineDesc.updateRenderPassDesc(getRenderPassDesc());