Add unittests for X11TopmostWindowFinder

ui/base/x/x11_util.cc

Index: ui/base/x/x11_util.cc
diff --git a/ui/base/x/x11_util.cc b/ui/base/x/x11_util.cc
index 8560f1bb594b79dbcf6d23f205aeef34b2382ca8..c9a8b89e29b466467854feefe1426a56e57bd50b 100644
--- a/ui/base/x/x11_util.cc
+++ b/ui/base/x/x11_util.cc
@@ -463,6 +463,37 @@ void HideHostCursor() {
   return invisible_cursor;
 }
 
+void SetUseOSWindowFrame(XID window, bool use_os_window_frame) {
+  // This data structure represents additional hints that we send to the window
+  // manager and has a direct lineage back to Motif, which defined this de facto
+  // standard. This struct doesn't seem 64-bit safe though, but it's what GDK
+  // does.
+  typedef struct {
+    unsigned long flags;
+    unsigned long functions;
+    unsigned long decorations;
+    long input_mode;
+    unsigned long status;
+  } MotifWmHints;
+
+  MotifWmHints motif_hints;
+  memset(&motif_hints, 0, sizeof(motif_hints));
+  // Signals that the reader of the _MOTIF_WM_HINTS property should pay
+  // attention to the value of |decorations|.
+  motif_hints.flags = (1L << 1);
+  motif_hints.decorations = use_os_window_frame ? 1 : 0;
+
+  ::Atom hint_atom = GetAtom("_MOTIF_WM_HINTS");
+  XChangeProperty(gfx::GetXDisplay(),
+                  window,
+                  hint_atom,
+                  hint_atom,
+                  32,
+                  PropModeReplace,
+                  reinterpret_cast<unsigned char*>(&motif_hints),
+                  sizeof(MotifWmHints)/sizeof(long));
+}
+
 bool IsShapeExtensionAvailable() {
   int dummy;
   static bool is_shape_available =
@@ -855,6 +886,13 @@ bool SetIntArrayProperty(XID window,
   return !err_tracker.FoundNewError();
 }
 
+bool SetAtomProperty(XID window,
+                     const std::string& name,
+                     const std::string& type,
+                     Atom value) {
+  return SetAtomArrayProperty(window, name, type, std::vector<Atom>(1, value));
+}
+
 bool SetAtomArrayProperty(XID window,
                           const std::string& name,
                           const std::string& type,