Add ability to have active window autohide shelf

ash/common/shelf/shelf_layout_manager.cc

Index: ash/common/shelf/shelf_layout_manager.cc
diff --git a/ash/common/shelf/shelf_layout_manager.cc b/ash/common/shelf/shelf_layout_manager.cc
index bc61c13515482543af83dee690225374a3cec07b..426a9b9f183f35731bf45595233b4bc7de640a69 100644
--- a/ash/common/shelf/shelf_layout_manager.cc
+++ b/ash/common/shelf/shelf_layout_manager.cc
@@ -26,6 +26,7 @@
 #include "ash/root_window_controller.h"
 #include "ash/shell.h"
 #include "ash/wm/screen_pinning_controller.h"
+#include "ash/wm/window_state_aura.h"
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/i18n/rtl.h"
@@ -248,9 +249,12 @@ void ShelfLayoutManager::UpdateVisibilityState() {
     // when we are in SHELF_AUTO_HIDE_ALWAYS_HIDDEN.
     wm::WorkspaceWindowState window_state(
         shelf_window->GetRootWindowController()->GetWorkspaceWindowState());
+
     switch (window_state) {
       case wm::WORKSPACE_WINDOW_STATE_FULL_SCREEN: {
-        if (IsShelfHiddenForFullscreen()) {
+        if (IsShelfAutoHideForFullscreenMaximized()) {
+          SetState(SHELF_AUTO_HIDE);
+        } else if (IsShelfHiddenForFullscreen()) {
           SetState(SHELF_HIDDEN);
         } else {
           // The shelf is sometimes not hidden when in immersive fullscreen.
@@ -260,7 +264,11 @@ void ShelfLayoutManager::UpdateVisibilityState() {
         break;
       }
       case wm::WORKSPACE_WINDOW_STATE_MAXIMIZED:
-        SetState(CalculateShelfVisibility());
+        if (IsShelfAutoHideForFullscreenMaximized()) {
+          SetState(SHELF_AUTO_HIDE);
+        } else {
+          SetState(CalculateShelfVisibility());
+        }
         break;
 
       case wm::WORKSPACE_WINDOW_STATE_WINDOW_OVERLAPS_SHELF:
@@ -1038,6 +1046,12 @@ bool ShelfLayoutManager::IsShelfHiddenForFullscreen() const {
          fullscreen_window->GetWindowState()->hide_shelf_when_fullscreen();
 }
 
+bool ShelfLayoutManager::IsShelfAutoHideForFullscreenMaximized() const {
+  wm::WindowState* active_window = wm::GetActiveWindowState();
+  return active_window &&
+         active_window->autohide_shelf_when_maximized_or_fullscreen();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // ShelfLayoutManager, Gesture functions: