Dynamically calculate the number of extension icons to show per row in overflow

ui/views/controls/menu/menu_item_view_unittest.cc

+// Copyright 2014 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 "ui/views/controls/menu/menu_item_view.h"
+
+#include "base/strings/string16.h"
+#include "base/strings/utf_string_conversions.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/views/controls/menu/submenu_view.h"
+#include "ui/views/view.h"
+
+namespace {
+
+// A simple View class that will match its height to the available width.
+class SquareView : public views::View {
+ public:
+  SquareView() {}
+  virtual ~SquareView() {}
+
+ private:
+  virtual gfx::Size GetPreferredSize() const OVERRIDE {
+    return gfx::Size(1, 1);
+  }
+  virtual int GetHeightForWidth(int width) const OVERRIDE {
+    return width;
+  }
+};
+
+// A MenuItemView implementation with a public destructor (so we can clean up
+// in tests).
+class TestMenuItemView : public views::MenuItemView {
+ public:
+  TestMenuItemView() : views::MenuItemView(NULL) {}
+  virtual ~TestMenuItemView() {}
+};
+
+}  // namespace
+
+TEST(MenuItemViewUnitTest, TestMenuItemViewWithFlexibleWidthChild) {
+  TestMenuItemView root_menu;
+  root_menu.set_owned_by_client();
+
+  // Append a normal MenuItemView.
+  views::MenuItemView* label_view =
+      root_menu.AppendMenuItemWithLabel(1, base::ASCIIToUTF16("item 1"));
+
+  // Append a second MenuItemView that has a child SquareView.
+  views::MenuItemView* flexible_view =
+      root_menu.AppendMenuItemWithLabel(2, base::string16());
+  flexible_view->AddChildView(new SquareView());
+  // Set margins to 0 so that we know width should match height.
+  flexible_view->SetMargins(0, 0);
+
+  views::SubmenuView* submenu = root_menu.GetSubmenu();
+
+  // The first item should be the label view.
+  ASSERT_EQ(label_view, submenu->GetMenuItemAt(0));
+  gfx::Size label_size = label_view->GetPreferredSize();
+
+  // The second item should be the flexible view.
+  ASSERT_EQ(flexible_view, submenu->GetMenuItemAt(1));
+  gfx::Size flexible_size = flexible_view->GetPreferredSize();
+
+  // The flexible view's "preferred size" should be 1x1...
+  EXPECT_EQ(flexible_size, gfx::Size(1, 1));
+
+  // ...but it should use whatever space is available to make a square.
+  int flex_height = flexible_view->GetHeightForWidth(label_size.width());
+  EXPECT_EQ(label_size.width(), flex_height);
+
+  // The submenu should be tall enough to allow for both menu items at the given
+  // width.
+  EXPECT_EQ(label_size.height() + flex_height,
+            submenu->GetPreferredSize().height());
+}