Auto merge of #21968 - UK992:mach-package, r=jdm

Windows: Add missing dependencies

Rebased https://github.com/servo/servo/pull/16445 and updated with Gstreamer DLLs.

About msi installer, there is also included gstreamer installer, should be removed and replaced by needed gstreamer DLLs or keep it at is it?

Fixes #16422.

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etc/taskcluster/decision_task.py

@@ -120,6 +120,7 @@ linux_build_env = {
 macos_build_env = {}
 windows_build_env = {
     "LIB": "%HOMEDRIVE%%HOMEPATH%\\gst\\gstreamer\\1.0\\x86_64\\lib;%LIB%",
+    "GSTREAMER_1_0_ROOT_X86_64": "%HOMEDRIVE%%HOMEPATH%\\gst\\gstreamer\\1.0\\x86_64\\",
 }
 windows_sparse_checkout = [
     "/*",
@@ -562,6 +563,12 @@ def windows_build_task(name):
         .with_repo(sparse_checkout=windows_sparse_checkout)
         .with_python2()
         .with_rustup()
+        .with_repacked_msi(
+            url="https://gstreamer.freedesktop.org/data/pkg/windows/" +
+                "1.14.3/gstreamer-1.0-x86_64-1.14.3.msi",
+            sha256="f4f20c713766ed6718b914b9ae57ed993a59ffe194e6ef530c8547508b4484d8",
+            path="gst",
+        )
         .with_repacked_msi(
             url="https://gstreamer.freedesktop.org/data/pkg/windows/" +
                 "1.14.3/gstreamer-1.0-devel-x86_64-1.14.3.msi",