[Device Service] Eliminate content::ScreenOrientationObserver.

This CL lets Blink talk directly with Device Service to consume the
mojo interface device.mojom.ScreenOrientationListener, then removes
content::ScreenOrientationObserver completely.

BUG=678545

Review-Url: https://codereview.chromium.org/2751513007
Cr-Commit-Position: refs/heads/master@{#457713}

content/renderer/BUILD.gn

@@ -339,8 +339,6 @@ target(link_target_type, "renderer") {
     "scheduler/resource_dispatch_throttler.h",
     "screen_orientation/screen_orientation_dispatcher.cc",
     "screen_orientation/screen_orientation_dispatcher.h",
-    "screen_orientation/screen_orientation_observer.cc",
-    "screen_orientation/screen_orientation_observer.h",
     "service_worker/embedded_worker_devtools_agent.cc",
     "service_worker/embedded_worker_devtools_agent.h",
     "service_worker/embedded_worker_dispatcher.cc",

content/renderer/renderer_blink_platform_impl.cc

@@ -66,7 +66,6 @@
 #include "content/renderer/mojo/blink_interface_provider_impl.h"
 #include "content/renderer/render_thread_impl.h"
 #include "content/renderer/renderer_clipboard_delegate.h"
-#include "content/renderer/screen_orientation/screen_orientation_observer.h"
 #include "content/renderer/webclipboard_impl.h"
 #include "content/renderer/webgraphicscontext3d_provider_impl.h"
 #include "content/renderer/webpublicsuffixlist_impl.h"
@@ -1132,8 +1131,6 @@ RendererBlinkPlatformImpl::CreatePlatformEventObserverFromType(
       return base::MakeUnique<DeviceLightEventPump>(thread);
     case blink::WebPlatformEventTypeGamepad:
       return base::MakeUnique<GamepadSharedMemoryReader>(thread);
-    case blink::WebPlatformEventTypeScreenOrientation:
-      return base::MakeUnique<ScreenOrientationObserver>();
     default:
       // A default statement is required to prevent compilation errors when
       // Blink adds a new type.

content/renderer/screen_orientation/screen_orientation_observer.cc

-// 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 "content/renderer/screen_orientation/screen_orientation_observer.h"
-
-#include "content/public/common/service_manager_connection.h"
-#include "content/renderer/render_thread_impl.h"
-#include "services/device/public/interfaces/constants.mojom.h"
-#include "services/service_manager/public/cpp/connector.h"
-
-namespace content {
-
-ScreenOrientationObserver::ScreenOrientationObserver() {
-}
-
-ScreenOrientationObserver::~ScreenOrientationObserver() {
-  StopIfObserving();
-}
-
-void ScreenOrientationObserver::Start(
-    blink::WebPlatformEventListener* listener) {
-  // This should never be called with a proper listener.
-  CHECK(listener == 0);
-  PlatformEventObserver<blink::WebPlatformEventListener>::Start(0);
-}
-
-void ScreenOrientationObserver::SendStartMessage() {
-  GetScreenOrientationListener()->Start();
-}
-
-void ScreenOrientationObserver::SendStopMessage() {
-  GetScreenOrientationListener()->Stop();
-}
-
-device::mojom::ScreenOrientationListener*
-ScreenOrientationObserver::GetScreenOrientationListener() {
-  if (!listener_) {
-    RenderThreadImpl::current()
-        ->GetServiceManagerConnection()
-        ->GetConnector()
-        ->BindInterface(device::mojom::kServiceName, &listener_);
-  }
-  return listener_.get();
-}
-
-} // namespace content

content/renderer/screen_orientation/screen_orientation_observer.h

-// 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 "content/public/renderer/platform_event_observer.h"
-#include "device/screen_orientation/public/interfaces/screen_orientation.mojom.h"
-
-namespace content {
-
-// ScreenOrientationObserver is a helper class implementing the
-// PlatformEventObserver template with blink::WebPlatformEventListener, which is
-// a pure virtual class because it doesn't expect listeners.
-// It is implemented on top of PlatformEventObserver to make sure it follows a
-// common code path even though it only uses part of this code path: it is not
-// expected to receive messages back but should send messages to start/stop
-// listening.
-// The intent of this class is to make sure that platforms that can't listen for
-// display rotations at a marginal cost can be told when to actually do it.
-class ScreenOrientationObserver
-    : public PlatformEventObserver<blink::WebPlatformEventListener> {
- public:
-  ScreenOrientationObserver();
-  ~ScreenOrientationObserver() override;
-
-  // Overriding this method just to make sure |listener| is always null.
-  void Start(blink::WebPlatformEventListener* listener) override;
-
- protected:
-  void SendStartMessage() override;
-  void SendStopMessage() override;
-
- private:
-  device::mojom::ScreenOrientationListener* GetScreenOrientationListener();
-
-  device::mojom::ScreenOrientationListenerPtr listener_;
-};
-
-}; // namespace content

third_party/WebKit/Source/modules/screen_orientation/BUILD.gn

@@ -17,4 +17,9 @@ blink_modules_sources("screen_orientation") {
     "ScreenScreenOrientation.cpp",
     "ScreenScreenOrientation.h",
   ]
+  deps = [
+    "//device/screen_orientation/public/interfaces:interfaces_blink",
+    "//services/device/public/interfaces:constants_blink",
+    "//third_party/WebKit/Source/platform",
+  ]
 }

third_party/WebKit/Source/modules/screen_orientation/DEPS

 include_rules = [
     "+bindings",
     "+core",
+    "+device/screen_orientation/public/interfaces/screen_orientation.mojom-blink.h",
     "-modules",
     "+modules/EventTargetModules.h",
     "+modules/ModulesExport.h",
     "+modules/screen_orientation",
     "+platform",
     "+public/platform",
+    "+services/device/public/interfaces/constants.mojom-blink.h",
     "-web",
 ]

third_party/WebKit/Source/modules/screen_orientation/ScreenOrientationDispatcher.cpp

@@ -4,7 +4,9 @@
 
 #include "modules/screen_orientation/ScreenOrientationDispatcher.h"
 
+#include "platform/ServiceConnector.h"
 #include "public/platform/Platform.h"
+#include "services/device/public/interfaces/constants.mojom-blink.h"
 
 namespace blink {
 
@@ -16,16 +18,27 @@ ScreenOrientationDispatcher& ScreenOrientationDispatcher::instance() {
 
 ScreenOrientationDispatcher::ScreenOrientationDispatcher() {}
 
+ScreenOrientationDispatcher::~ScreenOrientationDispatcher() {
+  DCHECK(!m_listener);
+}
+
 DEFINE_TRACE(ScreenOrientationDispatcher) {
   PlatformEventDispatcher::trace(visitor);
 }
 
 void ScreenOrientationDispatcher::startListening() {
-  Platform::current()->startListening(WebPlatformEventTypeScreenOrientation, 0);
+  DCHECK(!m_listener);
+
+  ServiceConnector::instance().connectToInterface(
+      device::mojom::blink::kServiceName, mojo::MakeRequest(&m_listener));
+  m_listener->Start();
 }
 
 void ScreenOrientationDispatcher::stopListening() {
-  Platform::current()->stopListening(WebPlatformEventTypeScreenOrientation);
+  DCHECK(m_listener);
+
+  m_listener->Stop();
+  m_listener.reset();
 }
 
 }  // namespace blink

third_party/WebKit/Source/modules/screen_orientation/ScreenOrientationDispatcher.h

@@ -6,6 +6,7 @@
 #define ScreenOrientationDispatcher_h
 
 #include "core/frame/PlatformEventDispatcher.h"
+#include "device/screen_orientation/public/interfaces/screen_orientation.mojom-blink.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
@@ -19,13 +20,16 @@ namespace blink {
 // ScreenOrientationDispatcher is listening, that means that the platform should
 // be polling if required.
 class ScreenOrientationDispatcher final
-    : public GarbageCollected<ScreenOrientationDispatcher>,
+    : public GarbageCollectedFinalized<ScreenOrientationDispatcher>,
       public PlatformEventDispatcher {
   USING_GARBAGE_COLLECTED_MIXIN(ScreenOrientationDispatcher);
+  WTF_MAKE_NONCOPYABLE(ScreenOrientationDispatcher);
 
  public:
   static ScreenOrientationDispatcher& instance();
 
+  ~ScreenOrientationDispatcher();
+
   DECLARE_VIRTUAL_TRACE();
 
  private:
@@ -34,6 +38,8 @@ class ScreenOrientationDispatcher final
   // Inherited from PlatformEventDispatcher.
   void startListening() override;
   void stopListening() override;
+
+  device::mojom::blink::ScreenOrientationListenerPtr m_listener;
 };
 
 }  // namespace blink

third_party/WebKit/public/platform/WebPlatformEventType.h

@@ -13,7 +13,6 @@ enum WebPlatformEventType {
   WebPlatformEventTypeDeviceOrientationAbsolute,
   WebPlatformEventTypeDeviceLight,
   WebPlatformEventTypeGamepad,
-  WebPlatformEventTypeScreenOrientation
 };
 
 }  // namespace blink