Auto merge of #24255 - ferjm:gst.log.uwp, r=jdm

Hook up GST_DEBUG log to visual studio output

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #23700

<strike>Depends on https://github.com/servo/media/pull/312</strike>

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components/servo/Cargo.toml

@@ -86,8 +86,9 @@ webxr-api = {git = "https://github.com/servo/webxr"}
 [target.'cfg(all(not(target_os = "windows"), not(target_os = "ios"), not(target_os="android"), not(target_arch="arm"), not(target_arch="aarch64")))'.dependencies]
 gaol = {git = "https://github.com/servo/gaol"}
 
-[target.'cfg(any(target_os = "android", target_arch = "x86_64", target_os = "windows"))'.dependencies.servo-media-gstreamer]
-git = "https://github.com/servo/media"
+[target.'cfg(any(target_os = "android", target_arch = "x86_64", target_os = "windows"))'.dependencies]
+gstreamer = "0.14.5"
+servo-media-gstreamer= {git = "https://github.com/servo/media"}
 
 [target.'cfg(not(any(target_os = "android", target_arch = "x86_64", target_os = "windows")))'.dependencies.servo-media-dummy]
 git = "https://github.com/servo/media"

components/servo/lib.rs

@@ -130,6 +130,34 @@ mod media_platform {
     use super::ServoMedia;
     use servo_media_gstreamer::GStreamerBackend;
 
+    #[cfg(target_os = "windows")]
+    fn set_gstreamer_log_handler() {
+        use gstreamer::{debug_add_log_function, debug_remove_default_log_function, DebugLevel};
+
+        debug_remove_default_log_function();
+        debug_add_log_function(|cat, level, file, function, line, _, message| {
+            let message = format!(
+                "{:?} {:?} {:?}:{:?}:{:?} {:?}",
+                cat.get_name(),
+                level,
+                file,
+                line,
+                function,
+                message
+            );
+            match level {
+                DebugLevel::Debug => debug!("{}", message),
+                DebugLevel::Error => error!("{}", message),
+                DebugLevel::Warning => warn!("{}", message),
+                DebugLevel::Fixme | DebugLevel::Info => info!("{}", message),
+                DebugLevel::Memdump | DebugLevel::Count | DebugLevel::Trace => {
+                    trace!("{}", message)
+                },
+                _ => (),
+            }
+        });
+    }
+
     #[cfg(windows)]
     pub fn init() {
         // UWP apps have the working directory set appropriately. Win32 apps
@@ -195,6 +223,9 @@ mod media_platform {
             },
         };
         ServoMedia::init_with_backend(backend);
+        if cfg!(feature = "uwp") {
+            set_gstreamer_log_handler();
+        }
     }
 
     #[cfg(not(windows))]