Screen.orientation lock API implementation for Windows8 and later.

content/browser/screen_orientation/screen_orientation_delegate_win.cc

+// Copyright 2016 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 "content/browser/screen_orientation/screen_orientation_delegate_win.h"
+
+#include <windows.h>
+#include "content/public/browser/screen_orientation_provider.h"
+
+namespace content {
+
+ScreenOrientationDelegateWin::ScreenOrientationDelegateWin() {
+  content::ScreenOrientationProvider::SetDelegate(this);
+}
+
+ScreenOrientationDelegateWin::~ScreenOrientationDelegateWin() {
+  content::ScreenOrientationProvider::SetDelegate(nullptr);
+}
+
+bool ScreenOrientationDelegateWin::FullScreenRequired(
+    content::WebContents* web_contents) {
+  return false;
+}
+
+static void GetCurrentDisplaySettings(bool *landscape, bool *flipped) {
+  DEVMODE dm;
+  ZeroMemory(&dm, sizeof(dm));
+  dm.dmSize = sizeof(dm);
+  if (!EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &dm))
+    return;
+  if (flipped) {
+    *flipped = (dm.dmDisplayOrientation == DMDO_270
+                || dm.dmDisplayOrientation == DMDO_180);
+  }
+  if (landscape)
+    *landscape = (dm.dmPelsWidth > dm.dmPelsHeight);
+}
+
+void ScreenOrientationDelegateWin::Lock(
+    content::WebContents* web_contents,
+    blink::WebScreenOrientationLockType lock_orientation) {
+  ORIENTATION_PREFERENCE prefs = ORIENTATION_PREFERENCE_NONE;
+  bool landscape = true;
+  bool flipped = false;
+  switch (lock_orientation) {
+    case blink::WebScreenOrientationLockPortraitPrimary:
+      prefs = ORIENTATION_PREFERENCE_PORTRAIT;
+      break;
+    case blink::WebScreenOrientationLockPortraitSecondary:
+      prefs = ORIENTATION_PREFERENCE_PORTRAIT_FLIPPED;
+      break;
+    case blink::WebScreenOrientationLockLandscapePrimary:
+      prefs = ORIENTATION_PREFERENCE_LANDSCAPE;
+      break;
+    case blink::WebScreenOrientationLockLandscapeSecondary:
+      prefs = ORIENTATION_PREFERENCE_LANDSCAPE_FLIPPED;
+      break;
+    case blink::WebScreenOrientationLockPortrait:
+      GetCurrentDisplaySettings(&landscape, &flipped);
+      prefs = (flipped && !landscape) ? ORIENTATION_PREFERENCE_PORTRAIT_FLIPPED
+                                      : ORIENTATION_PREFERENCE_PORTRAIT;
+      break;
+    case blink::WebScreenOrientationLockLandscape:
+      GetCurrentDisplaySettings(&landscape, &flipped);
+      prefs = (flipped && landscape) ? ORIENTATION_PREFERENCE_LANDSCAPE_FLIPPED
+                                     : ORIENTATION_PREFERENCE_LANDSCAPE;
+      break;
+    case blink::WebScreenOrientationLockNatural:
+      GetCurrentDisplaySettings(&landscape, &flipped);
+      prefs = landscape ? ORIENTATION_PREFERENCE_LANDSCAPE
+                        : ORIENTATION_PREFERENCE_PORTRAIT;
+      break;
+    case blink::WebScreenOrientationLockAny:
+      GetCurrentDisplaySettings(&landscape, &flipped);
+      if (landscape) {
+        prefs = flipped ? ORIENTATION_PREFERENCE_LANDSCAPE_FLIPPED
+                        : ORIENTATION_PREFERENCE_LANDSCAPE;
+      } else {
+        prefs = flipped ? ORIENTATION_PREFERENCE_PORTRAIT_FLIPPED
+                        : ORIENTATION_PREFERENCE_PORTRAIT;
+      }
+      break;
+    case blink::WebScreenOrientationLockDefault:
+    default:
+      break;
+  }
+  SetDisplayAutoRotationPreferences(prefs);
+}
+
+bool ScreenOrientationDelegateWin::ScreenOrientationProviderSupported() {
+  AR_STATE autoRotationState;
+  ZeroMemory(&autoRotationState, sizeof(AR_STATE));
+  return (GetAutoRotationState(&autoRotationState)
+          && (autoRotationState == AR_ENABLED));

[aleksandar.stojiljkovic, 2016/03/03 20:34:36]

It might be better to change this to:
&& !(autoRotationState & AR_NOSENSOR) && !(autoRotationState & AR_NOT_SUPPORTED)
For 2-in-1 laptops and for docked tablets it would set preferred orientation
although it wouldn't apply it immediately.
The orientation lock API is checking what is the state after this call, and it
would return error.
However, once tablet is undocked or when 2-in-1 switches to tablet mode, it
should go to screen orientation that is set in JS API.

1. If we keep "&& (autoRotationState == AR_ENABLED));" here, it would not allow
setting preferred orientation in laptop or docked mode.

2. If using "&& !(autoRotationState & AR_NOSENSOR) && !(autoRotationState &
AR_NOT_SUPPORTED)", it would allow setting preferred orientation but it would
return error in JS and orientation would change when entering tablet/undocked
mode.
 

+}
+
+void ScreenOrientationDelegateWin::Unlock(
+    content::WebContents* web_contents) {
+  SetDisplayAutoRotationPreferences(ORIENTATION_PREFERENCE_NONE);
+}
+
+}  // namespace content