A recent patched moved the desktop background beneath the system background, which breaks workspace animations. This makes the z-order as we want it (system background

underneath desktop background) and adds a test.

BUG=137342
TEST=covered by tests.
R=ben@chromium.org

Review URL: https://chromiumcodereview.appspot.com/10913100

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@155123 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 61 insertions, 1 deletions

diff --git a/ash/shell_unittest.cc b/ash/shell_unittest.cc
index d6b0d59..e9e7554 100644
--- a/ash/shell_unittest.cc
+++ b/ash/shell_unittest.cc
@@ -2,10 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "ash/shell.h"
+
+#include <algorithm>
+#include <vector>
+
 #include "ash/ash_switches.h"
 #include "ash/desktop_background/desktop_background_widget_controller.h"
 #include "ash/launcher/launcher.h"
-#include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ash/shell_window_ids.h"
 #include "ash/test/ash_test_base.h"
@@ -49,6 +53,8 @@ void ExpectAllContainers() {
   EXPECT_TRUE(Shell::GetContainer(
       root_window, internal::kShellWindowId_DesktopBackgroundContainer));
   EXPECT_TRUE(Shell::GetContainer(
+      root_window, internal::kShellWindowId_SystemBackgroundContainer));
+  EXPECT_TRUE(Shell::GetContainer(
       root_window, internal::kShellWindowId_DefaultContainer));
   EXPECT_TRUE(Shell::GetContainer(
       root_window, internal::kShellWindowId_AlwaysOnTopContainer));
@@ -330,6 +336,60 @@ TEST_F(ShellTest, FullscreenWindowHidesShelf) {
   widget->Close();
 }
 
+namespace {
+
+// Builds the list of parents from |window| to the root. The returned vector is
+// in reverse order (|window| is first).
+std::vector<aura::Window*> BuildPathToRoot(aura::Window* window) {
+  std::vector<aura::Window*> results;
+  while (window) {
+    results.push_back(window);
+    window = window->parent();
+  }
+  return results;
+}
+
+}  // namespace
+
+// The SystemBackgroundContainer needs to be behind the
+// DesktopBackgroundContainer, otherwise workspace animations don't line up.
+TEST_F(ShellTest, SystemBackgroundBehindDesktopBackground) {
+  aura::RootWindow* root_window = Shell::GetPrimaryRootWindow();
+  aura::Window* desktop = Shell::GetContainer(
+      root_window, internal::kShellWindowId_DesktopBackgroundContainer);
+  ASSERT_TRUE(desktop != NULL);
+  aura::Window* system_bg = Shell::GetContainer(
+      root_window, internal::kShellWindowId_SystemBackgroundContainer);
+  ASSERT_TRUE(system_bg != NULL);
+
+  std::vector<aura::Window*> desktop_parents(BuildPathToRoot(desktop));
+  std::vector<aura::Window*> system_bg_parents(BuildPathToRoot(system_bg));
+
+  for (size_t i = 0; i < system_bg_parents.size(); ++i) {
+    std::vector<aura::Window*>::iterator desktop_i =
+        std::find(desktop_parents.begin(), desktop_parents.end(),
+                  system_bg_parents[i]);
+    if (desktop_i != desktop_parents.end()) {
+      // Found the common parent.
+      ASSERT_NE(0u, i);
+      ASSERT_TRUE(desktop_i != desktop_parents.begin());
+      aura::Window* common_parent = system_bg_parents[i];
+      int system_child = static_cast<int>(std::find(
+          common_parent->children().begin(),
+          common_parent->children().end(), system_bg_parents[i - 1]) -
+          common_parent->children().begin());
+      int desktop_child = static_cast<int>(std::find(
+          common_parent->children().begin(),
+          common_parent->children().end(), *(desktop_i - 1)) -
+          common_parent->children().begin());
+      EXPECT_LT(system_child, desktop_child);
+      return;
+    }
+  }
+  EXPECT_TRUE(false) <<
+      "system background and desktop background need to have a common parent";
+}
+
 // This verifies WindowObservers are removed when a window is destroyed after
 // the Shell is destroyed. This scenario (aura::Windows being deleted after the
 // Shell) occurs if someone is holding a reference to an unparented Window, as