WorkspaceLayoutManager backdrop should fill entire region.

ash/wm/workspace/workspace_layout_manager_unittest.cc

Index: ash/wm/workspace/workspace_layout_manager_unittest.cc
diff --git a/ash/wm/workspace/workspace_layout_manager_unittest.cc b/ash/wm/workspace/workspace_layout_manager_unittest.cc
index 651f1f8cd1a49ebe8a9693638e09fb7b3fb87ccb..cb37449eabb1043491600780aa8e3c537e156eb3 100644
--- a/ash/wm/workspace/workspace_layout_manager_unittest.cc
+++ b/ash/wm/workspace/workspace_layout_manager_unittest.cc
@@ -4,6 +4,8 @@
 
 #include "ash/wm/workspace/workspace_layout_manager.h"
 
+#include <string>
+
 #include "ash/display/display_layout.h"
 #include "ash/display/display_manager.h"
 #include "ash/root_window_controller.h"
@@ -39,7 +41,7 @@ namespace {
 
 class MaximizeDelegateView : public views::WidgetDelegateView {
  public:
-  MaximizeDelegateView(const gfx::Rect& initial_bounds)
+  explicit MaximizeDelegateView(const gfx::Rect& initial_bounds)
       : initial_bounds_(initial_bounds) {
   }
   virtual ~MaximizeDelegateView() {}
@@ -788,9 +790,6 @@ class WorkspaceLayoutManagerBackdropTest : public test::AshTestBase {
     UpdateDisplay("800x600");
     default_container_ = Shell::GetContainer(Shell::GetPrimaryRootWindow(),
                                              kShellWindowId_DefaultContainer);
-    // We set the size to something smaller then the display to avoid resizing
-    // issues with the shelf.
-    default_container_->SetBounds(gfx::Rect(0, 0, 800, 500));
   }
 
   aura::Window* CreateTestWindow(const gfx::Rect& bounds) {
@@ -942,6 +941,32 @@ TEST_F(WorkspaceLayoutManagerBackdropTest, VerifyBackdropAndItsStacking) {
                                    window3.get()));
 }
 
+// Tests that when hidding the shelf, that the backdrop resizes to fill the
+// entire workspace area.
+TEST_F(WorkspaceLayoutManagerBackdropTest, ShelfVisibilityChangesBounds) {
+  ShelfLayoutManager* shelf_layout_manager =
+      Shell::GetPrimaryRootWindowController()->GetShelfLayoutManager();
+  ShowTopWindowBackdrop(true);
+  RunAllPendingInMessageLoop();
+
+  gfx::Rect initial_bounds = default_container()->children()[0]->bounds();

[flackr, 2014/06/17 15:05:31]

Not really clear what the shelf state is at this point. Maybe set or expect_eq
it?

[jonross, 2014/06/17 17:21:02]

Shelf should be visible, I've added an assert to verify, and for clarity.

+  shelf_layout_manager->SetAutoHideBehavior(SHELF_AUTO_HIDE_ALWAYS_HIDDEN);
+  shelf_layout_manager->UpdateVisibilityState();
+
+  // When the shelf is re-shown WorkspaceLayoutManager shrinks all children
+  // including the backdrop.
+  shelf_layout_manager->SetAutoHideBehavior(SHELF_AUTO_HIDE_BEHAVIOR_NEVER);
+  shelf_layout_manager->UpdateVisibilityState();
+  gfx::Rect reduced_bounds = default_container()->children()[0]->bounds();
+  EXPECT_LT(reduced_bounds.height(), initial_bounds.height());

[flackr, 2014/06/17 15:05:31]

So after hiding and showing the shelf the bounds are a bit smaller? Shouldn't
the bounds grow when the shelf is hidden and return to what they were after the
shelf is shown again?

[jonross, 2014/06/17 17:21:02]

The backdrop delegate is created with the size of the default container. This
extends it past the size of the shelf. However the delegate does not take into
account that WorkspaceLayoutManager triggers window manager events. (See
WorkspaceLayoutManager::AdjustAllWindowsBoundsForWorkAreaChange)

This causes the backdrop delegate to shrink its size when the shelf first comes
back. Then on subsequent shelf changes nothing was causing the size to update.
(It's not a maximized widget)

[flackr, 2014/06/17 23:48:33]

Does this manifest on device in any way? It sounds like a bug that it's not
created at the right size. Presumably it could be created using the workspace's
size? Can you file a bug and reference it here? Otherwise this is a really
strange expectation to see in the test.

+
+  shelf_layout_manager->SetAutoHideBehavior(SHELF_AUTO_HIDE_ALWAYS_HIDDEN);
+  shelf_layout_manager->UpdateVisibilityState();
+
+  EXPECT_GT(default_container()->children()[0]->bounds().height(),
+            reduced_bounds.height());
+}
+
 class WorkspaceLayoutManagerKeyboardTest : public test::AshTestBase {
  public:
   WorkspaceLayoutManagerKeyboardTest() {}
@@ -983,14 +1008,14 @@ class WorkspaceLayoutManagerKeyboardTest : public test::AshTestBase {
  private:
   gfx::Insets restore_work_area_insets_;
   gfx::Rect keyboard_bounds_;
-  WorkspaceLayoutManager *layout_manager_;
+  WorkspaceLayoutManager* layout_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkspaceLayoutManagerKeyboardTest);
 };
 
 class FakeTextInputClient : public ui::DummyTextInputClient {
  public:
-  FakeTextInputClient(gfx::NativeWindow window) : window_(window) {}
+  explicit FakeTextInputClient(gfx::NativeWindow window) : window_(window) {}
   virtual ~FakeTextInputClient() {}
 
   virtual gfx::NativeWindow GetAttachedWindow() const OVERRIDE {