Add a flag in StopCapture to allow event handler to choose event notification.

content/renderer/media/video_capture_impl.cc

Index: content/renderer/media/video_capture_impl.cc
===================================================================
--- content/renderer/media/video_capture_impl.cc	(revision 102594)
+++ content/renderer/media/video_capture_impl.cc	(working copy)
@@ -5,6 +5,7 @@
 #include "content/renderer/media/video_capture_impl.h"
 
 #include "base/stl_util.h"
+#include "base/synchronization/waitable_event.h"
 #include "content/common/child_process.h"
 #include "content/common/media/video_capture_messages.h"
 
@@ -94,9 +95,19 @@
                         capability));
 }
 
-void VideoCaptureImpl::StopCapture(media::VideoCapture::EventHandler* handler) {
-  ml_proxy_->PostTask(FROM_HERE,
-      NewRunnableMethod(this, &VideoCaptureImpl::DoStopCapture, handler));
+void VideoCaptureImpl::StopCapture(media::VideoCapture::EventHandler* handler,
+                                   bool need_notification) {
+  if (need_notification) {
+    ml_proxy_->PostTask(FROM_HERE,
+        NewRunnableMethod(this, &VideoCaptureImpl::DoStopCapture, handler,
+                          static_cast<base::WaitableEvent*>(NULL)));
+  } else {
+    base::WaitableEvent completion(false, false);
+    ml_proxy_->PostTask(FROM_HERE,
+        NewRunnableMethod(this, &VideoCaptureImpl::DoStopCapture, handler,
+                          &completion));
+    completion.Wait();
+  }
 }
 
 void VideoCaptureImpl::FeedBuffer(scoped_refptr<VideoFrameBuffer> buffer) {
@@ -213,20 +224,27 @@
 }
 
 void VideoCaptureImpl::DoStopCapture(
-    media::VideoCapture::EventHandler* handler) {
+    media::VideoCapture::EventHandler* handler,
+    base::WaitableEvent* completion) {
   DCHECK(ml_proxy_->BelongsToCurrentThread());
 
   ClientInfo::iterator it = pending_clients_.find(handler);
   if (it != pending_clients_.end()) {
-    handler->OnStopped(this);
     pending_clients_.erase(it);
+    if (!completion)
+      handler->OnStopped(this);
+    else
+      completion->Signal();
     return;
   }
 
   if (clients_.find(handler) == clients_.end())
     return;
 
-  handler->OnStopped(this);
+  if (!completion)
+    handler->OnStopped(this);
+  else
+    completion->Signal();
   clients_.erase(handler);
   master_clients_.remove(handler);