Allow shaped-desktop hosts to send shape only when it changes.

remoting/client/plugin/chromoting_instance.cc

Index: remoting/client/plugin/chromoting_instance.cc
diff --git a/remoting/client/plugin/chromoting_instance.cc b/remoting/client/plugin/chromoting_instance.cc
index 73210471bce3001c9e17e91e7f33c16ec55c9b59..9e8c291fe6f3dbc5fb8312bfcb497b1dd15a97d9 100644
--- a/remoting/client/plugin/chromoting_instance.cc
+++ b/remoting/client/plugin/chromoting_instance.cc
@@ -438,26 +438,29 @@ void ChromotingInstance::OnVideoSize(const webrtc::DesktopSize& size,
   PostLegacyJsonMessage("onDesktopSize", data.Pass());
 }
 
-void ChromotingInstance::OnVideoShape(const webrtc::DesktopRegion& shape) {
-  if (desktop_shape_ && shape.Equals(*desktop_shape_))
+void ChromotingInstance::OnVideoShape(const webrtc::DesktopRegion* shape) {
+  if ((shape && desktop_shape_ && shape->Equals(*desktop_shape_)) ||
+      (!shape && !desktop_shape_)) {
     return;
+  }
 
-  desktop_shape_.reset(new webrtc::DesktopRegion(shape));
-
-  scoped_ptr<base::ListValue> rects_value(new base::ListValue());
-  for (webrtc::DesktopRegion::Iterator i(shape); !i.IsAtEnd(); i.Advance()) {
-    const webrtc::DesktopRect& rect = i.rect();
-    scoped_ptr<base::ListValue> rect_value(new base::ListValue());
-    rect_value->AppendInteger(rect.left());
-    rect_value->AppendInteger(rect.top());
-    rect_value->AppendInteger(rect.width());
-    rect_value->AppendInteger(rect.height());
-    rects_value->Append(rect_value.release());
+  scoped_ptr<base::DictionaryValue> shape_message(new base::DictionaryValue());
+  if (shape) {
+    desktop_shape_ = make_scoped_ptr(new webrtc::DesktopRegion(*shape));
+    scoped_ptr<base::ListValue> rects_value(new base::ListValue());
+    for (webrtc::DesktopRegion::Iterator i(*shape); !i.IsAtEnd(); i.Advance()) {
+      const webrtc::DesktopRect& rect = i.rect();
+      scoped_ptr<base::ListValue> rect_value(new base::ListValue());
+      rect_value->AppendInteger(rect.left());
+      rect_value->AppendInteger(rect.top());
+      rect_value->AppendInteger(rect.width());
+      rect_value->AppendInteger(rect.height());
+      rects_value->Append(rect_value.release());
+    }
+    shape_message->Set("rects", rects_value.release());
   }
 
-  scoped_ptr<base::DictionaryValue> data(new base::DictionaryValue());
-  data->Set("rects", rects_value.release());
-  PostLegacyJsonMessage("onDesktopShape", data.Pass());
+  PostLegacyJsonMessage("onDesktopShape", shape_message.Pass());
 }
 
 void ChromotingInstance::OnVideoFrameDirtyRegion(