Use VkPipelineCaches during VkPipeline creation

src/gpu/vk/GrVkResourceProvider.h

Index: src/gpu/vk/GrVkResourceProvider.h
diff --git a/src/gpu/vk/GrVkResourceProvider.h b/src/gpu/vk/GrVkResourceProvider.h
index 245062ea8df4827f69713b115373063ecd3400ac..38d6c401879f8c9bf2f149be3932dd77c0785ca4 100644
--- a/src/gpu/vk/GrVkResourceProvider.h
+++ b/src/gpu/vk/GrVkResourceProvider.h
@@ -28,6 +28,9 @@ public:
     GrVkResourceProvider(GrVkGpu* gpu);
     ~GrVkResourceProvider();
 
+    // Set up any initial vk objects
+    void init();
+
     GrVkPipeline* createPipeline(const GrPipeline& pipeline,
                                  const GrPrimitiveProcessor& primProc,
                                  VkPipelineShaderStageCreateInfo* shaderStageInfo,
@@ -66,6 +69,9 @@ public:
 private:
     GrVkGpu* fGpu;
 
+    // Central cache for creating pipelines
+    VkPipelineCache fPipelineCache;
+
     // Array of RenderPasses that only have a single color attachment, optional stencil attachment,
     // optional resolve attachment, and only one subpass
     SkSTArray<4, GrVkRenderPass*> fSimpleRenderPasses;