Add IPC to query capabilities of video input devices.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 95a45927753fc3a64f770e520c67a380f60e3c38..d04b15b1420eeb26e7ba20eea3a705ddd3419cd0 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -2358,6 +2358,12 @@ bool WebContentsImpl::CheckMediaAccessPermission(const GURL& security_origin,
          delegate_->CheckMediaAccessPermission(this, security_origin, type);
 }
 
+std::string WebContentsImpl::GetDefaultMediaDeviceID(MediaStreamType type) {
+  if (!delegate_)
+    return std::string();
+  return delegate_->GetDefaultMediaDeviceID(this, type);
+}
+
 SessionStorageNamespace* WebContentsImpl::GetSessionStorageNamespace(
     SiteInstance* instance) {
   return controller_.GetSessionStorageNamespace(instance);