Add IPC to query capabilities of video input devices.

content/browser/frame_host/render_frame_host_delegate.cc

Index: content/browser/frame_host/render_frame_host_delegate.cc
diff --git a/content/browser/frame_host/render_frame_host_delegate.cc b/content/browser/frame_host/render_frame_host_delegate.cc
index 7410d178fa401ceba7e9c696637ae866a738cf68..7314dcbc4114839d89ae9520f8e17e1611bf3298 100644
--- a/content/browser/frame_host/render_frame_host_delegate.cc
+++ b/content/browser/frame_host/render_frame_host_delegate.cc
@@ -57,6 +57,11 @@ bool RenderFrameHostDelegate::CheckMediaAccessPermission(
   return false;
 }
 
+std::string RenderFrameHostDelegate::GetDefaultMediaDeviceID(
+    MediaStreamType type) {
+  return std::string();
+}
+
 AccessibilityMode RenderFrameHostDelegate::GetAccessibilityMode() const {
   return AccessibilityModeOff;
 }