CrOS Shelf: Ensure maximized auto-hide shelf is transparent in clamshell mode

Bug: 1031651
Change-Id: Ic6d663fc798078db3f5099e3bae4f2737a111503
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1973150Reviewed-by: Manu Cornet <manucornet@chromium.org>
Commit-Queue: Matthew Mourgos <mmourgos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#726679}

ash/shelf/shelf_layout_manager.cc

@@ -809,6 +809,12 @@ ShelfBackgroundType ShelfLayoutManager::GetShelfBackgroundType() const {
   }
 
   if (maximized) {
+    // When a window is maximized, if the auto-hide shelf is enabled and we are
+    // in clamshell mode, the shelf will keep the default transparent
+    // background.
+    if (!IsTabletModeEnabled() && state_.visibility_state == SHELF_AUTO_HIDE)
+      return ShelfBackgroundType::kDefaultBg;
+
     return ShelfBackgroundType::kMaximized;
   }
 

ash/shelf/shelf_layout_manager_unittest.cc

@@ -1418,7 +1418,7 @@ TEST_P(ShelfLayoutManagerTest, VisibleWhenLockScreenShowing) {
 
   UnlockScreen();
   EXPECT_EQ(SHELF_AUTO_HIDE, shelf->GetVisibilityState());
-  EXPECT_EQ(ShelfBackgroundType::kMaximized,
+  EXPECT_EQ(ShelfBackgroundType::kDefaultBg,
             GetShelfWidget()->GetBackgroundType());
 }
 
@@ -2637,8 +2637,8 @@ TEST_P(ShelfLayoutManagerTest, TabletModeTransitionWithAppListVisible) {
   EXPECT_EQ(ShelfBackgroundType::kInApp, GetShelfWidget()->GetBackgroundType());
 }
 
-// Verify that the auto-hide shelf has default background by default and has
-// maxmimized background when a window is maximized.
+// Verify that the auto-hide shelf has default background by default and still
+// has the default background when a window is maximized in clamshell mode.
 TEST_P(ShelfLayoutManagerTest, ShelfBackgroundColorAutoHide) {
   EXPECT_EQ(ShelfBackgroundType::kDefaultBg,
             GetShelfWidget()->GetBackgroundType());
@@ -2651,7 +2651,7 @@ TEST_P(ShelfLayoutManagerTest, ShelfBackgroundColorAutoHide) {
             GetShelfWidget()->GetBackgroundType());
 
   w1->SetProperty(aura::client::kShowStateKey, ui::SHOW_STATE_MAXIMIZED);
-  EXPECT_EQ(ShelfBackgroundType::kMaximized,
+  EXPECT_EQ(ShelfBackgroundType::kDefaultBg,
             GetShelfWidget()->GetBackgroundType());
 }