Support allowSRGBInputs on Vulkan (via secondary texture views)

src/gpu/vk/GrVkUtil.h

Index: src/gpu/vk/GrVkUtil.h
diff --git a/src/gpu/vk/GrVkUtil.h b/src/gpu/vk/GrVkUtil.h
index c2227ec02d73112b42bdfb7de4c1df4c847f4735..b81aff4ae36769aac5982ff8a0744fbda2ed9a26 100644
--- a/src/gpu/vk/GrVkUtil.h
+++ b/src/gpu/vk/GrVkUtil.h
@@ -35,6 +35,12 @@ bool GrPixelConfigToVkFormat(GrPixelConfig config, VkFormat* format);
 */
 bool GrVkFormatToPixelConfig(VkFormat format, GrPixelConfig* config);
 
+/**
+ * Returns true if the given vulkan texture format is sRGB encoded.
+ * Also provides the non-sRGB version, if there is one.
+ */
+bool GrVkFormatIsSRGB(VkFormat format, VkFormat* linearFormat);
+
 bool GrSampleCountToVkSampleCount(uint32_t samples, VkSampleCountFlagBits* vkSamples);
 
 #endif