Enable Dynamic Incognito Quota by default.

Incognito Dynamic Quota experiment is changed to enabled by default and
its arguments are modified to the value that was set by latest active
finch trials.

The following three ranges where experimented: 0.1 - 0.2, 0.1 - 0.15,
and 0.15 - 0.2.
Since there was no significant stability difference between the three,
kept the highest one which gives more quota and adds maximum
uncertainty to detection.

Bug: 1017120
Change-Id: I4039f37c3badad5b00552dd3c92bd734e5b245fb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2363751
Commit-Queue: Ramin Halavati <rhalavati@chromium.org>
Reviewed-by: Jarryd Goodman <jarrydg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800490}

storage/browser/quota/quota_features.cc

@@ -27,13 +27,13 @@ const base::Feature kQuotaUnlimitedPoolSize{"QuotaUnlimitedPoolSize",
 // IncognitoDynamicQuota enables dynamic assignment of quota to incognito mode
 // based on the physical memory size and removes the fixed upper cap for it.
 const base::Feature kIncognitoDynamicQuota{"IncognitoDynamicQuota",
-                                           base::FEATURE_DISABLED_BY_DEFAULT};
+                                           base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Dynamic quota for incognito mode would be set by a random fraction of
 // physical memory, between |IncognitoQuotaRatioLowerBound| and
 // |IncognitoQuotaRatioUpperBound|.
 constexpr base::FeatureParam<double> kIncognitoQuotaRatioLowerBound{
-    &kIncognitoDynamicQuota, "IncognitoQuotaRatioLowerBound", 0.1};
+    &kIncognitoDynamicQuota, "IncognitoQuotaRatioLowerBound", 0.15};
 constexpr base::FeatureParam<double> kIncognitoQuotaRatioUpperBound{
     &kIncognitoDynamicQuota, "IncognitoQuotaRatioUpperBound", 0.2};