Introduces window_finder_android.cc

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

Index: chrome/browser/ui/views/tabs/tab_drag_controller.cc
diff --git a/chrome/browser/ui/views/tabs/tab_drag_controller.cc b/chrome/browser/ui/views/tabs/tab_drag_controller.cc
index 2fbf5ed41cd1eb1e1f0c290d468c9783c0c3b51c..1e2d451dfeac38c2250f274d5384a84348b02d5e 100644
--- a/chrome/browser/ui/views/tabs/tab_drag_controller.cc
+++ b/chrome/browser/ui/views/tabs/tab_drag_controller.cc
@@ -1795,12 +1795,12 @@ gfx::NativeWindow TabDragController::GetLocalProcessWindow(
     const gfx::Point& screen_point,
     bool exclude_dragged_view) {
   std::set<gfx::NativeWindow> exclude;
-  if (exclude_dragged_view) {
-    gfx::NativeWindow dragged_window =
-        attached_tabstrip_->GetWidget()->GetNativeWindow();
-    if (dragged_window)
-      exclude.insert(dragged_window);
-  }
+  gfx::NativeWindow dragged_window =
+      attached_tabstrip_->GetWidget()->GetNativeWindow();
+  if (exclude_dragged_view && dragged_window)
+    exclude.insert(dragged_window);
+  gfx::NativeWindow root_window =
+      dragged_window ? dragged_window->GetRootWindow() : nullptr;

[mfomitchev, 2015/10/30 20:37:34]

Is it actually possible for dragged_window to be null?

[bshe, 2015/10/30 20:57:05]

Yes. It sounds strange. But the original code seems to think so (line 1801).
I also find this comment here:
https://code.google.com/p/chromium/codesearch/#chromium/src/ui/views/widget/d...
It might suggest the dragged_window could become null as for desktop aura native
widget, content_window is the native window.

[mfomitchev, 2015/10/30 21:28:33]

Should we just bail and return null in this case?
GetLocalProcessWindowAtPointImpl will crash if root_window is null...

[bshe, 2015/11/02 13:46:43]

I seems to me that it wont be null for aura android as we wont use the desktop
widget. But you are right, it is safer to add a check against it. Added in
window_finder_android.cc.

 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
   // Exclude windows which are pending deletion via Browser::TabStripEmpty().
   // These windows can be returned in the Linux Aura port because the browser
@@ -1815,8 +1815,6 @@ gfx::NativeWindow TabDragController::GetLocalProcessWindow(
       exclude.insert((*it)->window()->GetNativeWindow());
   }
 #endif
-  return GetLocalProcessWindowAtPoint(host_desktop_type_,
-                                      screen_point,
-                                      exclude);
-
+  return GetLocalProcessWindowAtPoint(host_desktop_type_, screen_point, exclude,
+                                      root_window);
 }