Make the memory reporting multi-process aware (#35863)

So far the memory reporter aggregates reports from all processes, and
runs the system reporter only in the main process. Instead it is
desirable to have per-process reports. We do so by:
- creating a ProcessReports struct that holds includes the pid in
addition to the reports themselves.
- running the system memory reporter also in content processes.
- updating the about:memory page to create one report per process, and
add useful information like the pid and the urls loaded in a given
process.

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---
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![image](https://github.com/user-attachments/assets/0bafe140-539d-4d6a-8316-639309a22d4a)

Signed-off-by: webbeef <me@webbeef.org>

components/net/resource_thread.rs

@@ -32,7 +32,9 @@ use net_traits::{
     FetchChannels, FetchTaskTarget, ResourceFetchTiming, ResourceThreads, ResourceTimingType,
     WebSocketDomAction, WebSocketNetworkEvent,
 };
-use profile_traits::mem::{ProfilerChan as MemProfilerChan, Report, ReportKind, ReportsChan};
+use profile_traits::mem::{
+    ProcessReports, ProfilerChan as MemProfilerChan, Report, ReportKind, ReportsChan,
+};
 use profile_traits::path;
 use profile_traits::time::ProfilerChan;
 use rustls::RootCertStore;
@@ -297,7 +299,7 @@ impl ResourceChannelManager {
             size: private_cache.size_of(&mut ops),
         };
 
-        msg.send(vec![public_report, private_report]);
+        msg.send(ProcessReports::new(vec![public_report, private_report]));
     }
 
     fn cancellation_listener(&self, request_id: RequestId) -> Option<Arc<CancellationListener>> {