Add start/stop listening Platform methods for Screen Orientation.

Source/modules/screen_orientation/ScreenOrientation.cpp

 // Copyright 2014 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 "config.h"
 #include "modules/screen_orientation/ScreenOrientation.h"
 
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/frame/LocalFrame.h"
 #include "modules/EventTargetModules.h"
 #include "modules/screen_orientation/LockOrientationCallback.h"
 #include "modules/screen_orientation/ScreenOrientationController.h"
+#include "public/platform/Platform.h"
 #include "public/platform/WebScreenOrientationType.h"
 
 // This code assumes that WebScreenOrientationType values are included in WebScreenOrientationLockType.
 #define COMPILE_ASSERT_MATCHING_ENUM(enum1, enum2) \
     COMPILE_ASSERT(static_cast<unsigned>(blink::enum1) == static_cast<unsigned>(blink::enum2), mismatching_types)
 COMPILE_ASSERT_MATCHING_ENUM(WebScreenOrientationPortraitPrimary, WebScreenOrientationLockPortraitPrimary);
 COMPILE_ASSERT_MATCHING_ENUM(WebScreenOrientationPortraitSecondary, WebScreenOrientationLockPortraitSecondary);
 COMPILE_ASSERT_MATCHING_ENUM(WebScreenOrientationLandscapePrimary, WebScreenOrientationLockLandscapePrimary);
 COMPILE_ASSERT_MATCHING_ENUM(WebScreenOrientationLandscapeSecondary, WebScreenOrientationLockLandscapeSecondary);
 
@@ skipping 73 matching lines @@
     orientation->controller()->setOrientation(orientation);
     return orientation;
 }
 
 ScreenOrientation::ScreenOrientation(LocalFrame* frame)
     : DOMWindowProperty(frame)
     , m_type(blink::WebScreenOrientationUndefined)
     , m_angle(0)
 {
     ScriptWrappable::init(this);
+
+    blink::Platform::current()->startScreenOrientationListening();
 }
 
 ScreenOrientation::~ScreenOrientation()
 {
+    blink::Platform::current()->stopScreenOrientationListening();

[Michael van Ouwerkerk, 2014/07/17 10:36:27]

Shouldn't this also be called when page visibility changes to !visible? This
could go in a followup patch if you prefer, but I think you could still add it.

 }
 
 const WTF::AtomicString& ScreenOrientation::interfaceName() const
 {
     return EventTargetNames::ScreenOrientation;
 }
 
 ExecutionContext* ScreenOrientation::executionContext() const
 {
     if (!m_frame)
@@ skipping 59 matching lines @@
 
     return ScreenOrientationController::from(*m_frame);
 }
 
 void ScreenOrientation::trace(Visitor* visitor)
 {
     EventTargetWithInlineData::trace(visitor);
 }
 
 } // namespace WebCore