Don't show rotation change notification in tablet mode unless it's changed by user.

ash/system/screen_layout_observer.cc

 // Copyright (c) 2012 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 "ash/system/screen_layout_observer.h"
 
 #include <memory>
 #include <utility>
 #include <vector>
 
 #include "ash/display/screen_orientation_controller_chromeos.h"
 #include "ash/metrics/user_metrics_action.h"
 #include "ash/resources/grit/ash_resources.h"
 #include "ash/session/session_controller.h"
 #include "ash/shell.h"
 #include "ash/shell_port.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "ash/system/devicetype_utils.h"
 #include "ash/system/system_notifier.h"
 #include "ash/system/tray/fixed_sized_image_view.h"
 #include "ash/system/tray/system_tray_controller.h"
 #include "ash/system/tray/tray_constants.h"
+#include "ash/wm/maximize_mode/maximize_mode_controller.h"
 #include "base/bind.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/display/display.h"
 #include "ui/display/manager/display_manager.h"
 #include "ui/display/types/display_constants.h"
 #include "ui/message_center/message_center.h"
 #include "ui/message_center/notification.h"
@@ skipping 231 matching lines @@
       return false;
     }
 
     if (iter.second.configured_ui_scale() !=
         old_iter->second.configured_ui_scale()) {
       *out_additional_message = l10n_util::GetStringFUTF16(
           IDS_ASH_STATUS_TRAY_DISPLAY_RESOLUTION_CHANGED,
           GetDisplayName(iter.first), GetDisplaySize(iter.first));
       return true;
     }
-    // We don't show rotation change notification when the rotation source is
-    // the accelerometer.
-    if (iter.second.active_rotation_source() !=
-            display::Display::ROTATION_SOURCE_ACCELEROMETER &&
-        iter.second.GetActiveRotation() !=
-            old_iter->second.GetActiveRotation()) {
-      int rotation_text_id = 0;
-      switch (iter.second.GetActiveRotation()) {
-        case display::Display::ROTATE_0:
-          rotation_text_id = IDS_ASH_STATUS_TRAY_DISPLAY_STANDARD_ORIENTATION;
-          break;
-        case display::Display::ROTATE_90:
-          rotation_text_id = IDS_ASH_STATUS_TRAY_DISPLAY_ORIENTATION_90;
-          break;
-        case display::Display::ROTATE_180:
-          rotation_text_id = IDS_ASH_STATUS_TRAY_DISPLAY_ORIENTATION_180;
-          break;
-        case display::Display::ROTATE_270:
-          rotation_text_id = IDS_ASH_STATUS_TRAY_DISPLAY_ORIENTATION_270;
-          break;
-      }
-      *out_additional_message = l10n_util::GetStringFUTF16(
-          IDS_ASH_STATUS_TRAY_DISPLAY_ROTATED, GetDisplayName(iter.first),
-          l10n_util::GetStringUTF16(rotation_text_id));
-      return true;
+    if (iter.second.GetActiveRotation() == old_iter->second.GetActiveRotation())
+      continue;
+
+    // We don't show rotation change notification if
+    // a) the source is accelerometer.
+    // b) if the device is in tablet mode, and source is not user.

[Mr4D (OOO till 08-26), 2017/05/10 04:37:48]

You might want to move this comment to line 275 and add a) the orientation does
not change.

[oshima, 2017/05/10 04:59:23]

Done

+    if (iter.second.active_rotation_source() ==
+        display::Display::ROTATION_SOURCE_ACCELEROMETER) {
+      continue;
     }
+    if (Shell::Get()
+            ->maximize_mode_controller()
+            ->IsMaximizeModeWindowManagerEnabled() &&
+        iter.second.active_rotation_source() !=
+            display::Display::ROTATION_SOURCE_USER) {
+      continue;
+    }
+
+    int rotation_text_id = 0;
+    switch (iter.second.GetActiveRotation()) {
+      case display::Display::ROTATE_0:
+        rotation_text_id = IDS_ASH_STATUS_TRAY_DISPLAY_STANDARD_ORIENTATION;
+        break;
+      case display::Display::ROTATE_90:
+        rotation_text_id = IDS_ASH_STATUS_TRAY_DISPLAY_ORIENTATION_90;
+        break;
+      case display::Display::ROTATE_180:
+        rotation_text_id = IDS_ASH_STATUS_TRAY_DISPLAY_ORIENTATION_180;
+        break;
+      case display::Display::ROTATE_270:
+        rotation_text_id = IDS_ASH_STATUS_TRAY_DISPLAY_ORIENTATION_270;
+        break;
+    }
+    *out_additional_message = l10n_util::GetStringFUTF16(
+        IDS_ASH_STATUS_TRAY_DISPLAY_ROTATED, GetDisplayName(iter.first),
+        l10n_util::GetStringUTF16(rotation_text_id));
+    return true;
   }
 
   // Found nothing special
   return false;
 }
 
 void ScreenLayoutObserver::CreateOrUpdateNotification(
     const base::string16& message,
     const base::string16& additional_message) {
   // Always remove the notification to make sure the notification appears
@@ skipping 84 matching lines @@
       return true;
 
     default:
       // Mirror mode was turned off; other messages should be shown e.g.
       // extended mode is on, ... etc.
       return false;
   }
 }
 
 }  // namespace ash