Mac: Sheets should be positioned between the content and everything above it.

chrome/browser/cocoa/browser_window_controller.mm

Index: chrome/browser/cocoa/browser_window_controller.mm
diff --git a/chrome/browser/cocoa/browser_window_controller.mm b/chrome/browser/cocoa/browser_window_controller.mm
index c0e8ebcbe1775d3b362974d29f06dfa6c5ce5fd3..1c2d9d759b7979791223fab95408a25bae8b3433 100644
--- a/chrome/browser/cocoa/browser_window_controller.mm
+++ b/chrome/browser/cocoa/browser_window_controller.mm
@@ -1155,8 +1155,11 @@ willPositionSheet:(NSWindow*)sheet
 - (NSRect)window:(NSWindow*)window
 willPositionSheet:(NSWindow*)sheet
        usingRect:(NSRect)defaultSheetRect {
-  NSRect windowFrame = [window frame];
-  defaultSheetRect.origin.y = windowFrame.size.height - 10;
+  // Any sheet should come from right above the visible content area.
+  NSRect toolbarFrame = [[toolbarController_ view] frame];
+  NSRect infobarFrame = [[infoBarContainerController_ view] frame];
+  defaultSheetRect.origin.y = toolbarFrame.origin.y - infobarFrame.size.height;
+
   return defaultSheetRect;
 }