[Android Refactor] Shorten FirstRunFlowSequencer#launch()

This CL makes FirstRunFlowSequencer#launch() shorter by extracting
the logic to check whether the generic FRE is active into a separate
function checkIsGenericFreActive().
This CL also changes maybeSwitchToTabbedMode() to only return whether
the FRE should use tabbed mode and to not modify the FRE launch intent.

This CL is in preparation to adding WebAPK-related complexity to
FirstRunFlowSequencer#launch()

BUG=None

Change-Id: If3605de61905edde800129f2d5e36c572432566f
Reviewed-on: https://chromium-review.googlesource.com/c/1355327
Commit-Queue: Peter Kotwicz <pkotwicz@chromium.org>
Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612485}

chrome/android/java/src/org/chromium/chrome/browser/firstrun/FirstRunFlowSequencer.java

@@ -350,15 +350,7 @@ public abstract class FirstRunFlowSequencer  {
         Log.d(TAG, "Redirecting user through FRE.");
         if ((intent.getFlags() & Intent.FLAG_ACTIVITY_NEW_TASK) != 0) {
             boolean isVrIntent = VrModuleProvider.getIntentDelegate().isVrIntent(intent);
-            boolean isGenericFreActive = false;
-            List<WeakReference<Activity>> activities = ApplicationStatus.getRunningActivities();
-            for (WeakReference<Activity> weakActivity : activities) {
-                Activity activity = weakActivity.get();
-                if (activity instanceof FirstRunActivity) {
-                    isGenericFreActive = true;
-                    break;
-                }
-            }
+            boolean isGenericFreActive = checkIsGenericFreActive();
 
             // Launch the Generic First Run Experience if it was previously active.
             Intent freIntent = null;
@@ -368,7 +360,9 @@ public abstract class FirstRunFlowSequencer  {
                 freIntent = createGenericFirstRunIntent(
                         caller, TextUtils.equals(intent.getAction(), Intent.ACTION_MAIN));
 
-                if (maybeSwitchToTabbedMode(caller, freIntent)) {
+                if (shouldSwitchToTabbedMode(caller)) {
+                    freIntent.setClass(caller, TabbedModeFirstRunActivity.class);
+
                     // We switched to TabbedModeFRE. We need to disable animation on the original
                     // intent, to make transition seamless.
                     intent = new Intent(intent);
@@ -396,6 +390,20 @@ public abstract class FirstRunFlowSequencer  {
         return true;
     }
 
+    /** Returns whether the generic FRE is active. */
+    private static boolean checkIsGenericFreActive() {
+        List<WeakReference<Activity>> activities = ApplicationStatus.getRunningActivities();
+        for (WeakReference<Activity> weakActivity : activities) {
+            Activity activity = weakActivity.get();
+            // TabbedModeFirstRunActivity extends FirstRunActivity. LightweightFirstRunActivity
+            // does not.
+            if (activity instanceof FirstRunActivity) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * On tablets, where FRE activity is a dialog, transitions from fillscreen activities
      * (the ones that use TabbedModeTheme, e.g. ChromeTabbedActivity) look ugly, because
@@ -405,9 +413,9 @@ public abstract class FirstRunFlowSequencer  {
      * To solve this, we added TabbedMode FRE activity, which has the same window background
      * as TabbedModeTheme activities, but shows content in a FRE-like dialog.
      *
-     * This function attempts to switch FRE to TabbedModeFRE if certain conditions are met.
+     * This function returns whether to use the TabbedModeFRE.
      */
-    private static boolean maybeSwitchToTabbedMode(Context caller, Intent freIntent) {
+    private static boolean shouldSwitchToTabbedMode(Context caller) {
         // Caller must be an activity.
         if (!(caller instanceof Activity)) return false;
 
@@ -419,10 +427,6 @@ public abstract class FirstRunFlowSequencer  {
         TypedArray a = caller.obtainStyledAttributes(new int[] {android.R.attr.windowBackground});
         int backgroundResourceId = a.getResourceId(0 /* index */, 0);
         a.recycle();
-        if (backgroundResourceId != R.drawable.window_background) return false;
-
-        // Switch FRE -> TabbedModeFRE.
-        freIntent.setClass(caller, TabbedModeFirstRunActivity.class);
-        return true;
+        return (backgroundResourceId == R.drawable.window_background);
     }
 }