USB: add help link config flag from Settings

Note: This cl is copied from the aosp/1783637 since
merge conflict issue.

Move the flag for the indication of the validity of help links to
the framework, as it is required here as well.

Set the visibility of help text in SystemUI for USB contamination
under this newly introduced flag.

Bug: 195448626
Test: adb shell dumpsys usb add-port "matrix" ufp
adb shell dumpsys usb set-contaminant-status "matrix" true

Change-Id: I50b7b447616f6b84fa170091c4e4a9dbf7ce6e45

core/res/res/values/config.xml

@@ -5557,4 +5557,7 @@
 
     <!-- Determines whether SafetyCenter feature is enabled. -->
     <bool name="config_enableSafetyCenter">true</bool>
+
+    <!-- Flag indicating if help links for Settings app should be enabled. -->
+    <bool name="config_settingsHelpLinksEnabled">false</bool>
 </resources>

core/res/res/values/symbols.xml

@@ -2338,6 +2338,7 @@
   <java-symbol type="string" name="nas_upgrade_notification_disable_action" />
   <java-symbol type="string" name="nas_upgrade_notification_learn_more_action" />
   <java-symbol type="string" name="nas_upgrade_notification_learn_more_content" />
+  <java-symbol type="bool" name="config_settingsHelpLinksEnabled" />
 
   <!-- ImfTest -->
   <java-symbol type="layout" name="auto_complete_list" />

packages/SystemUI/res/layout/contaminant_dialog.xml

@@ -63,7 +63,8 @@
 
         <TextView
             android:id="@+id/learnMore"
-            style="@style/USBContaminant.UserAction" />
+            style="@style/USBContaminant.UserAction"
+            android:visibility="gone" />
 
         <View
             android:layout_width="match_parent"

packages/SystemUI/src/com/android/systemui/usb/UsbContaminantActivity.java

@@ -70,6 +70,10 @@ public class UsbContaminantActivity extends Activity implements View.OnClickList
         mEnableUsb.setText(getString(R.string.usb_disable_contaminant_detection));
         mGotIt.setText(getString(R.string.got_it));
         mLearnMore.setText(getString(R.string.learn_more));
+        if (getResources().getBoolean(
+                com.android.internal.R.bool.config_settingsHelpLinksEnabled)) {
+            mLearnMore.setVisibility(View.VISIBLE);
+        }
 
         mEnableUsb.setOnClickListener(this);
         mGotIt.setOnClickListener(this);