Revert "Refactor code listening to platform events in content/renderer/."

content/renderer/device_sensors/device_sensor_event_pump.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.
 
 #ifndef CONTENT_RENDERER_DEVICE_SENSORS_DEVICE_SENSOR_EVENT_PUMP_H_
 #define CONTENT_RENDERER_DEVICE_SENSORS_DEVICE_SENSOR_EVENT_PUMP_H_
 
 #include "base/memory/shared_memory.h"
 #include "base/timer/timer.h"
-#include "content/public/renderer/platform_event_observer.h"
+#include "content/public/renderer/render_process_observer.h"
 
 namespace content {
+class RenderThread;
 
-template <typename ListenerType>
-class CONTENT_EXPORT DeviceSensorEventPump
-    : NON_EXPORTED_BASE(public PlatformEventObserver<ListenerType>) {
+class CONTENT_EXPORT DeviceSensorEventPump : public RenderProcessObserver {
  public:
   // Default delay between subsequent firing of events.
-  static const int kDefaultPumpDelayMillis = 50;
+  static const int kDefaultPumpDelayMillis;
 
-  // PlatformEventObserver
-  virtual void Start(blink::WebPlatformEventListener* listener) OVERRIDE {
-    DVLOG(2) << "requested start";
+  int GetDelayMillis() const;
 
-    if (state_ != STOPPED)
-      return;
-
-    DCHECK(!timer_.IsRunning());
-
-    PlatformEventObserver<ListenerType>::Start(listener);
-    state_ = PENDING_START;
-  }
-
-  virtual void Stop() OVERRIDE {
-    DVLOG(2) << "stop";
-
-    if (state_ == STOPPED)
-      return;
-
-    DCHECK((state_ == PENDING_START && !timer_.IsRunning()) ||
-        (state_ == RUNNING && timer_.IsRunning()));
-
-    if (timer_.IsRunning())
-      timer_.Stop();
-    PlatformEventObserver<ListenerType>::Stop();
-    state_ = STOPPED;
-  }
+  void Attach(RenderThread* thread);
+  virtual bool OnControlMessageReceived(const IPC::Message& message) = 0;
 
  protected:
-  explicit DeviceSensorEventPump(RenderThread* thread)
-      : PlatformEventObserver<ListenerType>(thread),
-        pump_delay_millis_(kDefaultPumpDelayMillis),
-        state_(STOPPED) {
-  }
+  // Constructor for a pump with default delay.
+  DeviceSensorEventPump();
 
-  virtual ~DeviceSensorEventPump() {
-  }
+  // Constructor for a pump with a given delay.
+  explicit DeviceSensorEventPump(int pump_delay_millis);
+  virtual ~DeviceSensorEventPump();
 
   // The pump is a tri-state automaton with allowed transitions as follows:
   // STOPPED -> PENDING_START
   // PENDING_START -> RUNNING
   // PENDING_START -> STOPPED
   // RUNNING -> STOPPED
   enum PumpState {
       STOPPED,
       RUNNING,
       PENDING_START
   };
 
-  void OnDidStart(base::SharedMemoryHandle handle) {
-    DVLOG(2) << "did start sensor event pump";
-
-    if (state_ != PENDING_START)
-      return;
-
-    DCHECK(!timer_.IsRunning());
-
-    if (InitializeReader(handle)) {
-      timer_.Start(FROM_HERE,
-                   base::TimeDelta::FromMilliseconds(pump_delay_millis_),
-                   this, &DeviceSensorEventPump::FireEvent);
-      state_ = RUNNING;
-    }
-  }
+  bool RequestStart();
+  void OnDidStart(base::SharedMemoryHandle handle);
+  bool Stop();
 
   virtual void FireEvent() = 0;
   virtual bool InitializeReader(base::SharedMemoryHandle handle) = 0;
+  virtual bool SendStartMessage() = 0;
+  virtual bool SendStopMessage() = 0;
 
   int pump_delay_millis_;
   PumpState state_;
   base::RepeatingTimer<DeviceSensorEventPump> timer_;
-
-  DISALLOW_COPY_AND_ASSIGN(DeviceSensorEventPump);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_DEVICE_SENSORS_DEVICE_SENSOR_EVENT_PUMP_H_