[MacViews] Position modal sheets using ModalDialogHost.

chrome/browser/ui/views/frame/browser_frame_mac.mm

Index: chrome/browser/ui/views/frame/browser_frame_mac.mm
diff --git a/chrome/browser/ui/views/frame/browser_frame_mac.mm b/chrome/browser/ui/views/frame/browser_frame_mac.mm
index 2d9aa266b431e81973ffbcc22024616e104a8b70..3e6bd346d883409b6083e6165c6b2c132fd39ce0 100644
--- a/chrome/browser/ui/views/frame/browser_frame_mac.mm
+++ b/chrome/browser/ui/views/frame/browser_frame_mac.mm
@@ -8,6 +8,7 @@
 #include "chrome/browser/ui/views/frame/browser_shutdown.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
 #import "chrome/browser/ui/views/frame/native_widget_mac_frameless_nswindow.h"
+#include "components/web_modal/web_contents_modal_dialog_host.h"
 #import "ui/base/cocoa/window_size_constants.h"
 
 BrowserFrameMac::BrowserFrameMac(BrowserFrame* browser_frame,
@@ -29,6 +30,17 @@ void BrowserFrameMac::OnWindowWillClose() {
   NativeWidgetMac::OnWindowWillClose();
 }
 
+int BrowserFrameMac::SheetPositionY() {
+  web_modal::WebContentsModalDialogHost* dialog_host =
+      browser_view_->GetWebContentsModalDialogHost();
+  NSView* host_view = dialog_host->GetHostView();
+  // Get the position of the host view relative to the window since
+  // ModalDialogHost::GetDialogPosition is relative to the host view.

[tapted, 2015/08/26 07:27:48]

nit: GetDialogPosition()

[jackhou1, 2015/08/27 05:38:09]

Done.

+  int host_view_y =
+      NSHeight([[host_view window] frame]) - NSMaxY([host_view frame]);

[tapted, 2015/08/26 07:27:48]

So I think this assumes host_view is the contentView (i.e. its frame is in the
same coordinate space as the window bounds), which might not be the case... I.e.
this only works if |dialog_host| and all its parent views are positioned at
(0,0) in their respective parents.

The idiomatic way to do this is something like

NSPoint pointInHost = flip([host_view frame],
dialog_host->GetDialogPosition(gfx::Size());
NSPoint pointInWindow = [host_view convertPoint:pointInHost toView:nil];
return gfx::Point(flip([window frame], pointInWindow)).y();

But.. I guess that's a bit horrible. If you don't like it, perhaps comment about
the assumption, and do something like

DCHECK_EQ(0, NSMinY([host_view frame]);  // Actually all the parents must be at
0 as well.
int height_delta = NSHeight([[host_view window] frame]) - NSHeight([host_view
frame]);

i.e. make it clear that it's only necessary to concern ourselves with the
difference in the heights of the host view and the window.

[jackhou1, 2015/08/27 05:38:09]

Changed to use -convertPoint to get the host_view's top edge.

+  return host_view_y + dialog_host->GetDialogPosition(gfx::Size()).y();
+}
+
 void BrowserFrameMac::InitNativeWidget(
     const views::Widget::InitParams& params) {
   views::NativeWidgetMac::InitNativeWidget(params);