Fix page zoom to be frame-centric for out-of-process frames.

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index a26e5841ed080501ffdc36a023cea8a21701e0a2..0292f96b1307ac340ef8817a3e67812dd0ab4512 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -275,7 +275,8 @@ bool RenderViewHostImpl::CreateRenderView(
     int proxy_route_id,
     int32_t max_page_id,
     const FrameReplicationState& replicated_frame_state,
-    bool window_was_created_with_opener) {
+    bool window_was_created_with_opener,
+    double zoom_level) {
   TRACE_EVENT0("renderer_host,navigation",
                "RenderViewHostImpl::CreateRenderView");
   DCHECK(!IsRenderViewLive()) << "Creating view twice";
@@ -337,6 +338,7 @@ bool RenderViewHostImpl::CreateRenderView(
   params.enable_auto_resize = GetWidget()->auto_resize_enabled();
   params.min_size = GetWidget()->min_size_for_auto_resize();
   params.max_size = GetWidget()->max_size_for_auto_resize();
+  params.preferred_subframe_zoom_level = zoom_level;

[alexmos, 2016/04/07 23:48:08]

It seems that some similar looking params (e.g., never_visible) are fetched from
WC via the delegate_, what do you think about that approach vs. adding another
param to CreateRenderView?  That would avoid touching the plumbing in tests and
passing 0.0 in places where it doesn't matter.

[wjmaclean, 2016/04/08 20:13:29]

It seemed to me that since RenderViewHostDelegate is "An interface implemented
by an object interested in knowing about the state of the RenderViewHost" and
since a zoom level is really a property of a WebContents, or a Page, that it
didn't seem to belong there.

But, I'm willing to be convinced otherwise.

[ncarter (slow), 2016/04/11 22:17:03]

I'm okay with either approach.

Practically, if you do it via the delegate it's harder to get things to work in
intersitials. But it looks like zoom doesn't work properly today in
interstitials anyway.

   GetWidget()->GetResizeParams(&params.initial_size);
 
   if (!Send(new ViewMsg_New(params)))