Set correct viewport size for an out of process iframe.

content/browser/frame_host/cross_process_frame_connector.cc

Index: content/browser/frame_host/cross_process_frame_connector.cc
diff --git a/content/browser/frame_host/cross_process_frame_connector.cc b/content/browser/frame_host/cross_process_frame_connector.cc
index 520eeb60fff67026a7a19304301accd9be4faf67..7eec85dd9901f47674fe4250c208d02bad0450d9 100644
--- a/content/browser/frame_host/cross_process_frame_connector.cc
+++ b/content/browser/frame_host/cross_process_frame_connector.cc
@@ -15,7 +15,8 @@ namespace content {
 CrossProcessFrameConnector::CrossProcessFrameConnector(
     RenderFrameHostImpl* frame_proxy_in_parent_renderer)
     : frame_proxy_in_parent_renderer_(frame_proxy_in_parent_renderer),
-      view_(NULL) {
+      view_(NULL),
+      device_scale_factor_(1) {
     frame_proxy_in_parent_renderer->set_cross_process_frame_connector(this);
 }
 
@@ -34,6 +35,8 @@ bool CrossProcessFrameConnector::OnMessageReceived(const IPC::Message& msg) {
                         OnCompositorFrameSwappedACK)
     IPC_MESSAGE_HANDLER(FrameHostMsg_ReclaimCompositorResources,
                         OnReclaimCompositorResources)
+    IPC_MESSAGE_HANDLER(FrameHostMsg_InitializeChildFrame,
+                        OnInitializeChildFrame)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP_EX()
 
@@ -116,6 +119,24 @@ void CrossProcessFrameConnector::OnReclaimCompositorResources(
                                                        params.ack);
 }
 
+void CrossProcessFrameConnector::OnInitializeChildFrame(gfx::Rect frame_rect,
+                                                        float scale_factor) {
+  if (scale_factor != device_scale_factor_) {
+    device_scale_factor_ = scale_factor;
+    if (view_) {
+      RenderWidgetHostImpl* child_widget =
+          RenderWidgetHostImpl::From(view_->GetRenderWidgetHost());
+      child_widget->NotifyScreenInfoChanged();
+    }
+  }
+
+  if (!frame_rect.size().IsEmpty()) {
+    child_frame_rect_ = frame_rect;
+    if (view_)
+      view_->SetSize(frame_rect.size());
+  }
+}
+
 gfx::Rect CrossProcessFrameConnector::ChildFrameRect() {
   return child_frame_rect_;
 }