Migrate MediaDevices.enumerateDevices to Mojo

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 865c2d937048285bfed1dabbb18b01306a388e9f..6d829c24772ea802b34334f194fb48d8aad39e26 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -20,6 +20,7 @@
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/browser/accessibility/browser_accessibility_state_impl.h"
 #include "content/browser/bluetooth/web_bluetooth_service_impl.h"
+#include "content/browser/browser_main_loop.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/devtools/render_frame_devtools_agent_host.h"
 #include "content/browser/download/mhtml_generation_manager.h"
@@ -43,6 +44,7 @@
 #include "content/browser/presentation/presentation_service_impl.h"
 #include "content/browser/renderer_host/input/input_router_impl.h"
 #include "content/browser/renderer_host/input/timeout_monitor.h"
+#include "content/browser/renderer_host/media/media_devices_dispatcher_host.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_view_host_delegate.h"
 #include "content/browser/renderer_host/render_view_host_delegate_view.h"
@@ -74,6 +76,7 @@
 #include "content/public/browser/permission_type.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_widget_host_view.h"
+#include "content/public/browser/resource_context.h"
 #include "content/public/browser/storage_partition.h"
 #include "content/public/browser/stream_handle.h"
 #include "content/public/browser/user_metrics.h"
@@ -2216,6 +2219,24 @@ void RenderFrameHostImpl::RegisterMojoInterfaces() {
         BrowserThread::GetTaskRunnerForThread(BrowserThread::IO));
   }
 
+#if defined(ENABLE_WEBRTC)
+  // BrowserMainLoop::GetInstance() may be null on unit tests.

[dcheng, 2016/10/10 17:51:52]

Out of curiosity, which unit tests does this trip up?

It'd be nicer not to have to do this, since it generally makes code a bit harder
to understand.

+  if (BrowserMainLoop::GetInstance()) {
+    MediaStreamManager* media_stream_manager =
+        BrowserMainLoop::GetInstance()->media_stream_manager();
+    GetInterfaceRegistry()->AddInterface(
+        base::Bind(&MediaDevicesDispatcherHost::Create, GetProcess()->GetID(),
+                   GetRoutingID(), GetProcess()
+                                       ->GetBrowserContext()
+                                       ->GetResourceContext()
+                                       ->GetMediaDeviceIDSalt(),
+                   base::Unretained(media_stream_manager),

[alexmos, 2016/10/10 17:56:13]

Can you please explain (and add a comment about) why base::Unretained is safe
here?  E.g., is it similar to the explanation for time_zone_monitor here? 
https://cs.chromium.org/chromium/src/content/browser/renderer_host/render_pro...

[Guido Urdaneta, 2016/10/10 18:34:42]

Done.

+                   base::CommandLine::ForCurrentProcess()->HasSwitch(
+                       switches::kUseFakeUIForMediaStream)),
+        BrowserThread::GetTaskRunnerForThread(BrowserThread::IO));
+  }
+#endif
+
   GetContentClient()->browser()->RegisterRenderFrameMojoInterfaces(
       GetInterfaceRegistry(), this);
 }