Fix style errors.
Replace instances of PassRefPtr with RefPtr in CaptureSession.
Replace instances of PassRefPtr with RefPtr in ReplayController, InspectorReplayAgent, and InspectorInstrumentation's web replay handlers.
Use forward declaration of ReplayRecording in CaptureSession. Use ASSERT_UNUSED to avoid release build error.
Replace commented out ReplayObserver calls with TODO comments.
Rename RecordingId and SessionId types to Recording/SessionIdentifier. Rename variables of these types from 'rid' to 'recordingId', etc.