17677 Roll src/third_party/skia 4b4efe4d6f1f..d468a1619a2f (1 commits) (cla: yes, waiting for tree to go green)

17680 Roll src/third_party/dart c9710e5059ad..2aecf30d2b2e (1 commits) (cla: yes, waiting for tree to go green)

17682 Enable required extension VK_KHR_external_semaphore_capabilities in shell_test (cla: yes)

17683 Use VK_LAYER_KHRONOS_validation only on Fuchsia (cla: yes, waiting for tree to go green)

17684 Enable Vulkan validation layers for shell_test (cla: yes, waiting for tree to go green)