Warn user when max number of tabs is reached

     Bug: http://b/issue?id=3123994
     A toast is shown when the max number of tabs is reached

Change-Id: I5008e227c91139147920fd214f184061f816a353
diff --git a/src/com/android/browser/Controller.java b/src/com/android/browser/Controller.java
index e4b0982..4b341da 100644
--- a/src/com/android/browser/Controller.java
+++ b/src/com/android/browser/Controller.java
@@ -2107,9 +2107,19 @@
         }
     }
 
+    @Override
+    public Tab openTabToHomePage() {
+        // check for max tabs
+        if (mTabControl.canCreateNewTab()) {
+            return openTabAndShow(mSettings.getHomePage(), false, null);
+        } else {
+            mUi.showMaxTabsWarning();
+            return null;
+        }
+    }
+
     // A wrapper function of {@link #openTabAndShow(UrlData, boolean, String)}
     // that accepts url as string.
-
     protected Tab openTabAndShow(String url, boolean closeOnExit, String appId) {
         return openTabAndShow(new UrlData(url), closeOnExit, appId);
     }
@@ -2166,8 +2176,10 @@
             addTab(tab);
             setActiveTab(tab);
             return tab;
+        } else {
+            mUi.showMaxTabsWarning();
+            return null;
         }
-        return null;
     }
 
     /**
@@ -2191,11 +2203,6 @@
     }
 
     @Override
-    public Tab openTabToHomePage() {
-        return openTabAndShow(mSettings.getHomePage(), false, null);
-    }
-
-    @Override
     public void closeCurrentTab() {
         // hide combo view if open
         removeComboView();