Disable GWP-ASan by default

Previously I had enabled GWP-ASan by default because it looked like it
was ready to launch with the default parameters. I'm having to tweak the
parameters to address some small perf regressions, so disable it by
default for now until it's actually ready to launch to 100% with the
given default parameters.

Change-Id: Ie1a723a70293da2fa4fa05d21025a09ea80230d0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1699512
Auto-Submit: Vlad Tsyrklevich <vtsyrklevich@chromium.org>
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#677049}

components/gwp_asan/client/gwp_asan.cc

@@ -59,7 +59,7 @@ constexpr double kDefaultProcessSamplingProbability = 0.2;
 constexpr int kDefaultProcessSamplingBoost2 = 5;
 
 const base::Feature kGwpAsanMalloc{"GwpAsanMalloc",
-                                   base::FEATURE_ENABLED_BY_DEFAULT};
+                                   base::FEATURE_DISABLED_BY_DEFAULT};
 const base::Feature kGwpAsanPartitionAlloc{"GwpAsanPartitionAlloc",
                                            base::FEATURE_DISABLED_BY_DEFAULT};