Add flag for assistive personal info experiment

The design doc for the experiment is at
go/e14s-assistive-personal-info-exp
Though the experiment is not approved yet. I think it better to add a
flag first and try implementation behind it.

Test: Tested with emulator on Linux
Bug: 1042084
Change-Id: I623edcca0a1c43d5e52cb4d6c96cb25581168369
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2018342Reviewed-by: Keith Lee <keithlee@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Commit-Queue: Jing Wang <jiwan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735643}

chromeos/constants/chromeos_features.cc

@@ -29,6 +29,10 @@ const base::Feature kArcAdbSideloadingFeature{
 const base::Feature kAutoScreenBrightness{"AutoScreenBrightness",
                                           base::FEATURE_ENABLED_BY_DEFAULT};
 
+// Controls whether to enable assist personal information.
+const base::Feature kAssistPersonalInfo{"AssistPersonalInfo",
+                                        base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Enables or disables more aggressive filtering out of Bluetooth devices with
 // "appearances" that are less likely to be pairable or useful.
 const base::Feature kBluetoothAggressiveAppearanceFilter{

chromeos/constants/chromeos_features.h

@@ -22,6 +22,8 @@ extern const base::Feature kArcAdbSideloadingFeature;
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
 extern const base::Feature kAutoScreenBrightness;
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
+extern const base::Feature kAssistPersonalInfo;
+COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
 extern const base::Feature kBluetoothAggressiveAppearanceFilter;
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
 extern const base::Feature kBluetoothPhoneFilter;