Include event_wrapper.h only where used.

It's currently used only by the VCMJitterBuffer and VCMReceiver
classes. Injection is needed by the VCMReceiverTimingTest test, which
defines a subclass(!) of EventWrapper.

Bug: webrtc:3380
Change-Id: I765be0ceac58e941928319cc426ba49f1cbdc5fa
Reviewed-on: https://webrtc-review.googlesource.com/c/113002
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25893}
diff --git a/modules/audio_device/linux/audio_device_alsa_linux.cc b/modules/audio_device/linux/audio_device_alsa_linux.cc
index bef4ef3..292193d 100644
--- a/modules/audio_device/linux/audio_device_alsa_linux.cc
+++ b/modules/audio_device/linux/audio_device_alsa_linux.cc
@@ -14,7 +14,6 @@
 #include "modules/audio_device/linux/audio_device_alsa_linux.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/system/arch.h"
-#include "system_wrappers/include/event_wrapper.h"
 #include "system_wrappers/include/sleep.h"
 
 WebRTCAlsaSymbolTable* GetAlsaSymbolTable() {
diff --git a/modules/audio_processing/audio_processing_unittest.cc b/modules/audio_processing/audio_processing_unittest.cc
index 6809ab9..90882d7 100644
--- a/modules/audio_processing/audio_processing_unittest.cc
+++ b/modules/audio_processing/audio_processing_unittest.cc
@@ -40,7 +40,6 @@
 #include "rtc_base/system/arch.h"
 #include "rtc_base/task_queue.h"
 #include "rtc_base/thread.h"
-#include "system_wrappers/include/event_wrapper.h"
 #include "test/gtest.h"
 #include "test/testsupport/fileutils.h"
 
diff --git a/modules/desktop_capture/mac/desktop_configuration_monitor.cc b/modules/desktop_capture/mac/desktop_configuration_monitor.cc
index 9a32f63..cee8e70 100644
--- a/modules/desktop_capture/mac/desktop_configuration_monitor.cc
+++ b/modules/desktop_capture/mac/desktop_configuration_monitor.cc
@@ -13,7 +13,6 @@
 #include "modules/desktop_capture/mac/desktop_configuration.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/trace_event.h"
-#include "system_wrappers/include/event_wrapper.h"
 
 namespace webrtc {
 
diff --git a/modules/video_coding/include/video_coding.h b/modules/video_coding/include/video_coding.h
index 653c120..33757b0 100644
--- a/modules/video_coding/include/video_coding.h
+++ b/modules/video_coding/include/video_coding.h
@@ -18,7 +18,6 @@
 #include "modules/include/module_common_types.h"
 #include "modules/video_coding/include/video_coding_defines.h"
 #include "rtc_base/deprecation.h"
-#include "system_wrappers/include/event_wrapper.h"
 
 namespace webrtc {
 
diff --git a/modules/video_coding/jitter_buffer.cc b/modules/video_coding/jitter_buffer.cc
index 2805fbb..4327ac9 100644
--- a/modules/video_coding/jitter_buffer.cc
+++ b/modules/video_coding/jitter_buffer.cc
@@ -28,7 +28,6 @@
 #include "rtc_base/system/fallthrough.h"
 #include "rtc_base/trace_event.h"
 #include "system_wrappers/include/clock.h"
-#include "system_wrappers/include/event_wrapper.h"
 #include "system_wrappers/include/field_trial.h"
 #include "system_wrappers/include/metrics.h"
 
diff --git a/modules/video_coding/jitter_buffer.h b/modules/video_coding/jitter_buffer.h
index 4826276..c8d7781 100644
--- a/modules/video_coding/jitter_buffer.h
+++ b/modules/video_coding/jitter_buffer.h
@@ -28,6 +28,7 @@
 #include "rtc_base/constructormagic.h"
 #include "rtc_base/criticalsection.h"
 #include "rtc_base/thread_annotations.h"
+#include "system_wrappers/include/event_wrapper.h"
 
 namespace webrtc {
 
@@ -35,7 +36,6 @@
 
 // forward declarations
 class Clock;
-class EventWrapper;
 class VCMFrameBuffer;
 class VCMPacket;
 class VCMEncodedFrame;
diff --git a/modules/video_coding/receiver.h b/modules/video_coding/receiver.h
index 503cae7..97692e0 100644
--- a/modules/video_coding/receiver.h
+++ b/modules/video_coding/receiver.h
@@ -20,6 +20,7 @@
 #include "modules/video_coding/packet.h"
 #include "modules/video_coding/timing.h"
 #include "rtc_base/criticalsection.h"
+#include "system_wrappers/include/event_wrapper.h"
 
 namespace webrtc {
 
diff --git a/sdk/objc/unittests/RTCAudioDeviceModule_xctest.mm b/sdk/objc/unittests/RTCAudioDeviceModule_xctest.mm
index 55d48c2..c2b5c6a 100644
--- a/sdk/objc/unittests/RTCAudioDeviceModule_xctest.mm
+++ b/sdk/objc/unittests/RTCAudioDeviceModule_xctest.mm
@@ -14,8 +14,6 @@
 #import "sdk/objc/native/api/audio_device_module.h"
 #endif
 
-#include "system_wrappers/include/event_wrapper.h"
-
 #include "rtc_base/scoped_ref_ptr.h"
 
 typedef int32_t(^NeedMorePlayDataBlock)(const size_t nSamples,