Reland "Enable sync trusted vault support by default"

This is a reland of f52179a5

The feature was disabled by default before branching because some
implementation parts were missing on Android.

Original change's description:
> Enable sync trusted vault support by default
>
> The feature is in a working state can be enabled by default.
>
> Bug: 1000146
> Change-Id: I66ef6f65d97234f47eaa76d1daafb8d3637692ed
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2000702
> Reviewed-by: Marc Treib <treib@chromium.org>
> Commit-Queue: Mikel Astiz <mastiz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#731898}

Bug: 1000146
Change-Id: If2c11c87bbc021daaa6656f9e85b592302dd8327
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2035966Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738548}

chrome/common/chrome_features.cc

@@ -709,8 +709,8 @@ const base::Feature kSoundContentSetting{"SoundContentSetting",
 
 #if !defined(OS_ANDROID)
 // Enables or disables the Javascript API to propagate sync encryption keys.
-const base::Feature kSyncEncryptionKeysWebApi{
-    "SyncEncryptionKeysWebApi", base::FEATURE_DISABLED_BY_DEFAULT};
+const base::Feature kSyncEncryptionKeysWebApi{"SyncEncryptionKeysWebApi",
+                                              base::FEATURE_ENABLED_BY_DEFAULT};
 #endif  // !defined(OS_ANDROID)
 
 #if defined(OS_CHROMEOS)

components/sync/engine/sync_engine_switches.cc

@@ -26,7 +26,7 @@ const base::Feature kSyncUseScryptForNewCustomPassphrases{
     "SyncUseScryptForNewCustomPassphrases", base::FEATURE_ENABLED_BY_DEFAULT};
 
 const base::Feature kSyncSupportTrustedVaultPassphrase{
-    "SyncSupportTrustedVaultPassphrase", base::FEATURE_DISABLED_BY_DEFAULT};
+    "SyncSupportTrustedVaultPassphrase", base::FEATURE_ENABLED_BY_DEFAULT};
 
 // If enabled sync cycle ends by collecting contributions from all datatypes
 // and having less than max_commit_batch_size() entries to commit. If disabled