Makes the touch tabstrip scroll so that tabs opened in the background

chrome/browser/ui/views/tabs/touch_tab_strip_layout_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/tabs/touch_tab_strip_layout.h"
 
 #include <string>
 
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
@@ skipping 214 matching lines @@
 }
 
 // Assertions for AddTab().
 TEST_F(TouchTabStripLayoutTest, AddTab) {
   struct TestData {
     CommonTestData common_data;
     int add_index;
     bool add_active;
     bool add_mini;
   } test_data[] = {
+    // Adding a background tab test cases.
+    { { 0, 300, 100, -10, 2, 0, 1, "0 90 180 198 200", "0 16 106 196 198 200"},
+      3, false, false },
+    { { 0, 300, 100, -10, 2, 0, 1, "0 90 180 198 200", "0 2 4 20 110 200"},
+      5, false, false },
+    { { 0, 300, 100, -10, 2, 0, 1, "0 90 180 198 200", "0 90 180 196 198 200"},
+      2, false, false },
+    { { 0, 300, 100, -10, 2, 0, 1, "0 90 180 198 200", "0 2 4 94 184 200"},
+      0, false, false },
+
     { { 4, 200, 100, -10, 2, 1, 2, "0 4 10 100", "0 0 8 10 100"},
       1, false, true },
     { { 4, 200, 100, -10, 2, 1, 2, "0 4 10 100", "0 0 8 98 100"},
       1, true, true },
     { { 4, 200, 100, -10, 2, 1, 2, "0 4 10 100", "0 0 8 98 100"},
       0, true, true },
     { { 0, 200, 100, -10, 2, 0, 2, "0 2 10 100", "0 4 94 98 100"},
       0, true, true },
 
     { { 0, 200, 100, -10, 2, 0, 0, "0 90 92 92 94 96 98 100",
@@ skipping 209 matching lines @@
 
 // Assertions around SetXAndMiniCount.
 TEST_F(TouchTabStripLayoutTest, SetXAndMiniCount) {
   // Verifies we don't crash when transitioning to all mini-tabs.
   PrepareChildViews(1);
   layout_.reset(new TouchTabStripLayout(
                     gfx::Size(100, 10), -10, 2, 4, &view_model_));
   Reset(layout_.get(), 0, 400, 0, 0);
   layout_->SetXAndMiniCount(0, 1);
 }