Revert to enumerating all X windows if the Window Manager doesn't support _NET_CLIENT_LIST_STACKING.

BUG=14004
TEST=Drag tabs in and out of tabstrip in xmonad window manager.
Review URL: http://codereview.chromium.org/141061

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@18949 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 42 insertions, 15 deletions

diff --git a/chrome/browser/dock_info_gtk.cc b/chrome/browser/dock_info_gtk.cc
index c54e4ba..403b65d 100644
--- a/chrome/browser/dock_info_gtk.cc
+++ b/chrome/browser/dock_info_gtk.cc
@@ -19,7 +19,7 @@
 //
 // Base class used to locate a window. A subclass need only override
 // ShouldStopIterating to determine when iteration should stop.
-class BaseWindowFinder : public gtk_util::EnumerateWindowsDelegate {
+class BaseWindowFinder : public x11_util::EnumerateWindowsDelegate {
  public:
   explicit BaseWindowFinder(const std::set<GtkWidget*>& ignore) {
     std::set<GtkWidget*>::iterator iter;
@@ -100,7 +100,7 @@ class TopMostFinder : public BaseWindowFinder {
       target_(window),
       screen_loc_(screen_loc),
       is_top_most_(false) {
-    gtk_util::EnumerateChildWindows(this);
+    gtk_util::EnumerateTopLevelWindows(this);
   }
 
   // The window we're looking for.
@@ -163,7 +163,7 @@ class LocalProcessWindowFinder : public BaseWindowFinder {
     : BaseWindowFinder(ignore),
       screen_loc_(screen_loc),
       result_(0) {
-    gtk_util::EnumerateChildWindows(this);
+    gtk_util::EnumerateTopLevelWindows(this);
   }
 
   // Position of the mouse.
diff --git a/chrome/common/gtk_util.cc b/chrome/common/gtk_util.cc
index 4c9f052..f89d5a8 100644
--- a/chrome/common/gtk_util.cc
+++ b/chrome/common/gtk_util.cc
@@ -216,10 +216,15 @@ bool IsScreenComposited() {
   return gdk_screen_is_composited(screen) == TRUE;
 }
 
-void EnumerateChildWindows(EnumerateWindowsDelegate* delegate) {
+void EnumerateTopLevelWindows(x11_util::EnumerateWindowsDelegate* delegate) {
   GdkScreen* screen = gdk_screen_get_default();
   GList* stack = gdk_screen_get_window_stack(screen);
-  DCHECK(stack);
+  if (!stack) {
+    // Window Manager doesn't support _NET_CLIENT_LIST_STACKING, so fall back
+    // to old school enumeration of all X windows.
+    x11_util::EnumerateAllWindows(delegate);
+    return;
+  }
 
   for (GList* iter = g_list_last(stack); iter; iter = iter->prev) {
     GdkWindow* window = static_cast<GdkWindow*>(iter->data);
diff --git a/chrome/common/gtk_util.h b/chrome/common/gtk_util.h
index b996c07..2f38092 100644
--- a/chrome/common/gtk_util.h
+++ b/chrome/common/gtk_util.h
@@ -88,17 +88,8 @@ std::string ConvertAcceleratorsFromWindowsStyle(const std::string& label);
 // Returns true if the screen is composited, false otherwise.
 bool IsScreenComposited();
 
-// Implementers of this interface receive a notification for every top-level
-// gdk window of the current display.
-class EnumerateWindowsDelegate {
- public:
-  // |xid| is the X Window ID of the enumerated window.  Return true to stop
-  // further iteration.
-  virtual bool ShouldStopIterating(XID xid) = 0;
-};
-
 // Enumerates the top-level gdk windows of the current display.
-void EnumerateChildWindows(EnumerateWindowsDelegate* delegate);
+void EnumerateTopLevelWindows(x11_util::EnumerateWindowsDelegate* delegate);
 
 // Set that a button causes a page navigation. In particular, it will accept
 // middle clicks. Warning: only call this *after* you have connected your
diff --git a/chrome/common/x11_util.cc b/chrome/common/x11_util.cc
index 522921f..da3eb7d 100644
--- a/chrome/common/x11_util.cc
+++ b/chrome/common/x11_util.cc
@@ -161,6 +161,25 @@ bool GetWindowRect(XID window, gfx::Rect* rect) {
   return true;
 }
 
+bool EnumerateAllWindows(EnumerateWindowsDelegate* delegate) {
+  XID root = GetX11RootWindow();
+  XID parent;
+  XID* children;
+  unsigned int num_children;
+  int status = XQueryTree(GetXDisplay(), root, &root, &parent,
+                          &children, &num_children);
+  if (status == 0)
+    return false;
+
+  for (unsigned int i = 0; i < num_children; i++) {
+    if (delegate->ShouldStopIterating(children[i]))
+      break;
+  }
+
+  XFree(children);
+  return true;
+}
+
 XRenderPictFormat* GetRenderVisualFormat(Display* dpy, Visual* visual) {
   static XRenderPictFormat* pictformat = NULL;
   if (pictformat)
diff --git a/chrome/common/x11_util.h b/chrome/common/x11_util.h
index 012b020..bcf0d0a 100644
--- a/chrome/common/x11_util.h
+++ b/chrome/common/x11_util.h
@@ -60,6 +60,18 @@ bool IsWindowVisible(XID window);
 // Returns the bounds of |window|.
 bool GetWindowRect(XID window, gfx::Rect* rect);
 
+// Implementers of this interface receive a notification for every X window of
+// the main display.
+class EnumerateWindowsDelegate {
+ public:
+  // |xid| is the X Window ID of the enumerated window.  Return true to stop
+  // further iteration.
+  virtual bool ShouldStopIterating(XID xid) = 0;
+};
+
+// Enumerates all windows in the current display
+bool EnumerateAllWindows(EnumerateWindowsDelegate* delegate);
+
 // Return a handle to a server side pixmap. |shared_memory_key| is a SysV
 // IPC key. The shared memory region must contain 32-bit pixels.
 XID AttachSharedMemory(Display* display, int shared_memory_support);