[Android] Reland CommandLine reset listeners.

chrome/android/java/src/org/chromium/chrome/browser/util/FeatureUtilities.java

Index: chrome/android/java/src/org/chromium/chrome/browser/util/FeatureUtilities.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/util/FeatureUtilities.java b/chrome/android/java/src/org/chromium/chrome/browser/util/FeatureUtilities.java
index 112ab3cd6ff88984bb598ec5d2fec0fa99ea0597..b32c299cf10aec82394ebcbaf4f97c3cef09a69e 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/util/FeatureUtilities.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/util/FeatureUtilities.java
@@ -33,7 +33,8 @@ public class FeatureUtilities {
     private static Boolean sHasGoogleAccountAuthenticator;
     private static Boolean sHasRecognitionIntentHandler;
     private static Boolean sDocumentModeDisabled;
-    private static Boolean sCustomTabVisible;
+    /** Used to track if cached command line flags should be refreshed. */
+    private static CommandLine.ResetListener sResetListener = null;
 
     /**
      * Determines whether or not the {@link RecognizerIntent#ACTION_WEB_SEARCH} {@link Intent}
@@ -98,6 +99,7 @@ public class FeatureUtilities {
      */
     public static boolean isDocumentMode(Context context) {
         if (sDocumentModeDisabled == null && CommandLine.isInitialized()) {
+            initResetListener();
             sDocumentModeDisabled = CommandLine.getInstance().hasSwitch(
                     ChromeSwitches.DISABLE_DOCUMENT_MODE);
         }
@@ -130,7 +132,6 @@ public class FeatureUtilities {
      * @param visible Whether a custom tab is visible.
      */
     public static void setCustomTabVisible(boolean visible) {
-        sCustomTabVisible = visible;
         nativeSetCustomTabVisible(visible);
     }
 
@@ -138,10 +139,19 @@ public class FeatureUtilities {
      * @return Whether a custom tab is visible.
      */
     public static boolean getCustomTabVisible() {
-        if (sCustomTabVisible == null) {
-            sCustomTabVisible = nativeGetCustomTabVisible();
-        }
-        return sCustomTabVisible;
+        return nativeGetCustomTabVisible();
+    }
+
+    private static void initResetListener() {
+        if (sResetListener != null) return;
+
+        sResetListener = new CommandLine.ResetListener() {
+            @Override
+            public void onCommandLineReset() {
+                sDocumentModeDisabled = null;
+            }
+        };
+        CommandLine.addResetListener(sResetListener);
     }
 
     private static native void nativeSetDocumentModeEnabled(boolean enabled);