Remove Windows snapshot code.

ui/snapshot/BUILD.gn

Index: ui/snapshot/BUILD.gn
diff --git a/ui/snapshot/BUILD.gn b/ui/snapshot/BUILD.gn
index f294800a9577bdb70c6e0b055835f3d87de05010..929aa3c978c0f235a4338782203b2008159cfe0f 100644
--- a/ui/snapshot/BUILD.gn
+++ b/ui/snapshot/BUILD.gn
@@ -14,8 +14,6 @@ component("snapshot") {
     "snapshot_export.h",
     "snapshot_ios.mm",
     "snapshot_mac.mm",
-    "snapshot_win.cc",
-    "snapshot_win.h",
   ]
 
   defines = [ "SNAPSHOT_IMPLEMENTATION" ]
@@ -83,15 +81,3 @@ test("snapshot_unittests") {
     sources -= [ "snapshot_aura_unittest.cc" ]
   }
 }
-
-if (is_win) {
-  source_set("test_support") {
-    sources = [
-      "test/snapshot_desktop.h",
-      "test/snapshot_desktop_win.cc",
-    ]
-    deps = [
-      ":snapshot",
-    ]
-  }
-}