Reland "Tracing: Move the tracing service in-process again to figure out test flakes"

This reverts commit 8b42fd6c.

Reason for revert: Flakes https://findit-for-me.appspot.com/waterfall/flake/flake-culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vOGI0MmZkNmM5MmZiNjY2MWNmYzNlOTIzNWM4NmYwMjU2MjZkZjA4ZQw

Original change's description:
> Revert "Tracing: Move the tracing service in-process again to figure out test flakes"
> 
> This reverts commit 6b27bca8.
> 
> Reason for revert: Should be fixed with https://chromium-review.googlesource.com/c/chromium/src/+/1474309/
> 
> Original change's description:
> > Tracing: Move the tracing service in-process again to figure out test flakes
> > 
> > Effectively temporarily reverting https://chromium-review.googlesource.com/c/chromium/src/+/1412016
> > 
> > Bug: 914579, 929142
> > Change-Id: I443e41fee17f6f09ca5cf5c243dbf330bafef6f8
> > Reviewed-on: https://chromium-review.googlesource.com/c/1456871
> > Commit-Queue: oysteine <oysteine@chromium.org>
> > Reviewed-by: ssid <ssid@chromium.org>
> > Reviewed-by: Alexei Filippov <alph@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#629738}
> 
> TBR=alph@chromium.org,oysteine@chromium.org,ssid@chromium.org
> 
> # Not skipping CQ checks because original CL landed > 1 day ago.
> 
> Bug: 914579, 929142
> Change-Id: I9585a500916c0d90b16901572823a3c7c14bbbbb
> Reviewed-on: https://chromium-review.googlesource.com/c/1477877
> Reviewed-by: oysteine <oysteine@chromium.org>
> Reviewed-by: ssid <ssid@chromium.org>
> Commit-Queue: oysteine <oysteine@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#634229}

TBR=alph@chromium.org,oysteine@chromium.org,ssid@chromium.org

Change-Id: I87f62967a2a0006b3b2f7a8c91bd44a26306643d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 914579, 929142
Reviewed-on: https://chromium-review.googlesource.com/c/1483250Reviewed-by: oysteine <oysteine@chromium.org>
Commit-Queue: oysteine <oysteine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634677}

services/tracing/public/cpp/tracing_features.cc

@@ -20,14 +20,8 @@ const base::Feature kTracingPerfettoBackend{"TracingPerfettoBackend",
                                             base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Runs the tracing service as an in-process browser service.
-const base::Feature kTracingServiceInProcess {
-  "TracingServiceInProcess",
-#if defined(OS_ANDROID)
-      base::FEATURE_ENABLED_BY_DEFAULT
-#else
-      base::FEATURE_DISABLED_BY_DEFAULT
-#endif
-};
+const base::Feature kTracingServiceInProcess{"TracingServiceInProcess",
+                                             base::FEATURE_ENABLED_BY_DEFAULT};
 
 }  // namespace features