Fixed tab dragging which was broken on high DPI windows for scales other than 100%.

chrome/browser/ui/views/tabs/window_finder_win.cc

Index: chrome/browser/ui/views/tabs/window_finder_win.cc
diff --git a/chrome/browser/ui/views/tabs/window_finder_win.cc b/chrome/browser/ui/views/tabs/window_finder_win.cc
index eff768ef2747e22a1bded33bab6a49fd970a491a..c2a2a238d5cc400b26f07df38778570c7077edd6 100644
--- a/chrome/browser/ui/views/tabs/window_finder_win.cc
+++ b/chrome/browser/ui/views/tabs/window_finder_win.cc
@@ -8,6 +8,7 @@
 #include "base/win/windows_version.h"
 #include "ui/aura/window.h"
 #include "ui/gfx/screen.h"
+#include "ui/gfx/win/dpi.h"
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_win.h"
 #include "ui/views/win/hwnd_util.h"
 
@@ -158,14 +159,16 @@ class LocalProcessWindowFinder : public BaseWindowFinder {
   static gfx::NativeWindow GetProcessWindowAtPoint(
       const gfx::Point& screen_loc,
       const std::set<HWND>& ignore) {
-    LocalProcessWindowFinder finder(screen_loc, ignore);
+    gfx::Point screen_loc_in_pixels = gfx::win::DIPToScreenPoint(screen_loc);
+    LocalProcessWindowFinder finder(screen_loc_in_pixels, ignore);

[sky, 2014/04/28 13:44:48]

Can we make LocalProcessWindowFinder and TopMostFinder take DIPs? If not, make
it clearer in descriptions that they take pixels, eg IsTopMostWindowAtPixel..

[ananta, 2014/04/28 18:13:08]

Done. Changed to continue passing in screen coordinates in DIPs. We convert to
pixels in the constructors of these classes.

     // Windows 8 has a window that appears first in the list of iterated
     // windows, yet is not visually on top of everything.
     // TODO(sky): figure out a better way to ignore this window.
     if (finder.result_ &&
         ((base::win::OSInfo::GetInstance()->version() >=
           base::win::VERSION_WIN8) ||
-         TopMostFinder::IsTopMostWindowAtPoint(finder.result_, screen_loc,
+         TopMostFinder::IsTopMostWindowAtPoint(finder.result_,
+                                               screen_loc_in_pixels,
                                                ignore))) {
       return views::DesktopWindowTreeHostWin::GetContentWindowForHWND(
           finder.result_);