Add offset to memory allocations

src/gpu/vk/GrVkMemory.h

Index: src/gpu/vk/GrVkMemory.h
diff --git a/src/gpu/vk/GrVkMemory.h b/src/gpu/vk/GrVkMemory.h
index 2e61451514251ba05b2be74a521edaf12d293030..55b4392ab8ff80fced8766307c05326a0f3312b6 100644
--- a/src/gpu/vk/GrVkMemory.h
+++ b/src/gpu/vk/GrVkMemory.h
@@ -20,12 +20,16 @@ namespace GrVkMemory {
     bool AllocAndBindBufferMemory(const GrVkGpu* gpu,
                                   VkBuffer buffer,
                                   const VkMemoryPropertyFlags flags,
-                                  VkDeviceMemory* memory);
+                                  VkDeviceMemory* memory,
+                                  VkDeviceSize* offset);
+    void FreeBufferMemory(const GrVkGpu* gpu, VkDeviceMemory memory, VkDeviceSize offset);
 
     bool AllocAndBindImageMemory(const GrVkGpu* gpu,
                                  VkImage image,
                                  const VkMemoryPropertyFlags flags,
-                                 VkDeviceMemory* memory);
+                                 VkDeviceMemory* memory,
+                                 VkDeviceSize* offset);
+    void FreeImageMemory(const GrVkGpu* gpu, VkDeviceMemory memory, VkDeviceSize offset);
 
     VkPipelineStageFlags LayoutToPipelineStageFlags(const VkImageLayout layout);