Use XDamage in Virtual Me2Me.

remoting/host/capturer_linux.cc

Index: remoting/host/capturer_linux.cc
diff --git a/remoting/host/capturer_linux.cc b/remoting/host/capturer_linux.cc
index 239aa169a43c9583a9a470ba2e87065bce6234a7..9c907168108fdc3a5441599a9b5416ac1bdc2523 100644
--- a/remoting/host/capturer_linux.cc
+++ b/remoting/host/capturer_linux.cc
@@ -23,10 +23,12 @@ namespace {
 
 static const int kBytesPerPixel = 4;
 
+// Default to false, since many systems have broken XDamage support - see
+// http://crbug.com/73423.
+static bool g_should_use_x_damage = false;
+
 static bool ShouldUseXDamage() {
-  // For now, always use full-screen polling instead of the DAMAGE extension,
-  // as this extension is broken on many current systems OOTB.
-  return false;
+  return g_should_use_x_damage;
 }
 
 // A class representing a full-frame pixel buffer
@@ -513,4 +515,9 @@ Capturer* Capturer::Create() {
   return capturer;
 }
 
+// static
+void Capturer::EnableXDamage(bool enable) {
+  g_should_use_x_damage = enable;
+}
+
 }  // namespace remoting