From 7505fe3457a1ea1b438138ed49e8637eb852583c Mon Sep 17 00:00:00 2001
From: Jonathan Kew <jkew@mozilla.com>
Date: Wed, 2 Mar 2016 12:15:19 +0000
Subject: [PATCH] Bug 1252347 - Provide missing implementations of
 nsIBaseWindow::SetPositionDesktopPix. r=emk

---
 docshell/base/nsDocShell.cpp              | 12 ++++++++----
 embedding/browser/nsDocShellTreeOwner.cpp | 11 +++++++----
 embedding/browser/nsWebBrowser.cpp        | 14 ++++++++++----
 3 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 587d6a871d1..eb6472d28f1 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -5820,10 +5820,14 @@ nsDocShell::SetPosition(int32_t aX, int32_t aY)
 NS_IMETHODIMP
 nsDocShell::SetPositionDesktopPix(int32_t aX, int32_t aY)
 {
-  // Added to nsIBaseWindow in bug 1247335;
-  // implement if a use-case is found.
-  NS_ASSERTION(false, "implement me!");
-  return NS_ERROR_NOT_IMPLEMENTED;
+  nsCOMPtr<nsIBaseWindow> ownerWindow(do_QueryInterface(mTreeOwner));
+  if (ownerWindow) {
+    return ownerWindow->SetPositionDesktopPix(aX, aY);
+  }
+
+  double scale = 1.0;
+  GetDevicePixelsPerDesktopPixel(&scale);
+  return SetPosition(NSToIntRound(aX * scale), NSToIntRound(aY * scale));
 }
 
 NS_IMETHODIMP
diff --git a/embedding/browser/nsDocShellTreeOwner.cpp b/embedding/browser/nsDocShellTreeOwner.cpp
index dfe990e498f..03443645ce1 100644
--- a/embedding/browser/nsDocShellTreeOwner.cpp
+++ b/embedding/browser/nsDocShellTreeOwner.cpp
@@ -573,10 +573,13 @@ nsDocShellTreeOwner::GetDevicePixelsPerDesktopPixel(double* aScale)
 NS_IMETHODIMP
 nsDocShellTreeOwner::SetPositionDesktopPix(int32_t aX, int32_t aY)
 {
-  // Added to nsIBaseWindow in bug 1247335;
-  // implement if a use-case is found.
-  NS_ASSERTION(false, "implement me!");
-  return NS_ERROR_NOT_IMPLEMENTED;
+  if (mWebBrowser) {
+    return mWebBrowser->SetPositionDesktopPix(aX, aY);
+  }
+
+  double scale = 1.0;
+  GetDevicePixelsPerDesktopPixel(&scale);
+  return SetPosition(NSToIntRound(aX * scale), NSToIntRound(aY * scale));
 }
 
 NS_IMETHODIMP
diff --git a/embedding/browser/nsWebBrowser.cpp b/embedding/browser/nsWebBrowser.cpp
index d656503d394..532b443ed52 100644
--- a/embedding/browser/nsWebBrowser.cpp
+++ b/embedding/browser/nsWebBrowser.cpp
@@ -1305,10 +1305,16 @@ nsWebBrowser::GetDevicePixelsPerDesktopPixel(double* aScale)
 NS_IMETHODIMP
 nsWebBrowser::SetPositionDesktopPix(int32_t aX, int32_t aY)
 {
-  // Added to nsIBaseWindow in bug 1247335;
-  // implement if a use-case is found.
-  NS_ASSERTION(false, "implement me!");
-  return NS_ERROR_NOT_IMPLEMENTED;
+  // XXX jfkthame
+  // It's not clear to me whether this will be fully correct across
+  // potential multi-screen, mixed-DPI configurations for all platforms;
+  // we might need to add code paths that make it possible to pass the
+  // desktop-pix parameters all the way through to the native widget,
+  // to avoid the risk of device-pixel coords mapping to the wrong
+  // display on OS X with mixed retina/non-retina screens.
+  double scale = 1.0;
+  GetDevicePixelsPerDesktopPixel(&scale);
+  return SetPosition(NSToIntRound(aX * scale), NSToIntRound(aY * scale));
 }
 
 NS_IMETHODIMP