Herb: Show an icon allowing the user to open a tab in Chrome

chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
index 265f36545028202e4e0f601fb3ac3a3c38d6442d..0ebe3452143802c08c15b1c0c8af7f9c34d14b70 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
@@ -48,6 +48,7 @@ import org.chromium.chrome.browser.compositor.layouts.eventfilter.EventFilter;
 import org.chromium.chrome.browser.compositor.layouts.phone.StackLayout;
 import org.chromium.chrome.browser.cookies.CookiesFetcher;
 import org.chromium.chrome.browser.device.DeviceClassManager;
+import org.chromium.chrome.browser.document.ChromeLauncherActivity;
 import org.chromium.chrome.browser.document.DocumentUma;
 import org.chromium.chrome.browser.enhancedbookmarks.EnhancedBookmarkUtils;
 import org.chromium.chrome.browser.firstrun.FirstRunActivity;
@@ -81,6 +82,7 @@ import org.chromium.chrome.browser.tabmodel.TabModelUtils;
 import org.chromium.chrome.browser.tabmodel.TabWindowManager;
 import org.chromium.chrome.browser.toolbar.ToolbarControlContainer;
 import org.chromium.chrome.browser.util.FeatureUtilities;
+import org.chromium.chrome.browser.util.IntentUtils;
 import org.chromium.chrome.browser.widget.emptybackground.EmptyBackgroundViewWrapper;
 import org.chromium.chrome.browser.widget.findinpage.FindToolbarManager;
 import org.chromium.content.browser.ContentVideoView;
@@ -467,7 +469,7 @@ public class ChromeTabbedActivity extends ChromeActivity implements OverviewMode
             getToolbarManager().getToolbar().setReturnButtonListener(new OnClickListener() {
                 @Override
                 public void onClick(View v) {
-                    if (getActivityTab() != null) closeForegroundTab();
+                    if (getActivityTab() != null) handleBackPressedWithoutBackStack();
                 }
             });
 
@@ -695,7 +697,8 @@ public class ChromeTabbedActivity extends ChromeActivity implements OverviewMode
                     break;
                 case OPEN_NEW_TAB:
                     Tab newTab = launchIntent(url, referer, headers, externalAppId, true, intent);
-                    newTab.setIsAllowedToReturnToExternalApp(true);
+                    newTab.setIsAllowedToReturnToExternalApp(IntentUtils.safeGetBooleanExtra(intent,
+                            ChromeLauncherActivity.EXTRA_IS_ALLOWED_TO_RETURN_TO_PARENT, true));
                     RecordUserAction.record("MobileReceivedExternalIntent");
                     break;
                 case OPEN_NEW_INCOGNITO_TAB:
@@ -1012,7 +1015,7 @@ public class ChromeTabbedActivity extends ChromeActivity implements OverviewMode
 
         if (!getToolbarManager().back()) {
             Log.i(TAG, "handleBackPressed() - no back stack");
-            if (closeForegroundTab()) return true;
+            if (handleBackPressedWithoutBackStack()) return true;
         } else {
             Log.i(TAG, "handleBackPressed() - moving back in navigation");
             RecordUserAction.record("SystemBackForNavigation");
@@ -1024,11 +1027,13 @@ public class ChromeTabbedActivity extends ChromeActivity implements OverviewMode
     }
 
     /**
-     * Closes the foreground tab, potentially sending the user back to the app that launched Chrome.
+     * Additional logic for handling situations where a user hits a 'back' or 'return' button.
+     *
+     * May result in closing the foreground tab or returning to the app that opened Chrome.
      *
      * @return Whether the tab closed was opened for a help page.
      */
-    private boolean closeForegroundTab() {
+    private boolean handleBackPressedWithoutBackStack() {
         final Tab currentTab = getActivityTab();
         final TabLaunchType type = currentTab.getLaunchType();
         final int parentId = currentTab.getParentId();
@@ -1043,12 +1048,19 @@ public class ChromeTabbedActivity extends ChromeActivity implements OverviewMode
             return true;
         }
 
+        // Herb is currently specced to disallow closing an externally launched tab in any scenario
+        // where the back button is pressed.
+        boolean isAllowedToCloseTabForExternalApp = true;
+        if (!TextUtils.isEmpty(ChromePreferenceManager.getHerbFlavor())) {
+            isAllowedToCloseTabForExternalApp = false;
+        }
+
         // [true]: Reached the bottom of the back stack on a tab the user did not explicitly
         // create (i.e. it was created by an external app or opening a link in background, etc).
         // [false]: Reached the bottom of the back stack on a tab that the user explicitly
         // created (e.g. selecting "new tab" from menu).
         final boolean shouldCloseTab = type == TabLaunchType.FROM_LINK
-                || type == TabLaunchType.FROM_EXTERNAL_APP
+                || (type == TabLaunchType.FROM_EXTERNAL_APP && isAllowedToCloseTabForExternalApp)
                 || type == TabLaunchType.FROM_LONGPRESS_FOREGROUND
                 || type == TabLaunchType.FROM_LONGPRESS_BACKGROUND
                 || (type == TabLaunchType.FROM_RESTORE && parentId != Tab.INVALID_TAB_ID);