[Aura] Support always-on-top top level window.

BUG=97256,102582
TEST=AlwaysOnTop related tests in ShellTest should pass.


Review URL: http://codereview.chromium.org/8387043

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@109990 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 20 insertions, 6 deletions

diff --git a/ui/base/x/x11_util.cc b/ui/base/x/x11_util.cc
index dada148..aa11de8 100644
--- a/ui/base/x/x11_util.cc
+++ b/ui/base/x/x11_util.cc
@@ -114,12 +114,7 @@ class XCursorCache {
  public:
    XCursorCache() {}
   ~XCursorCache() {
-    Display* display = base::MessagePumpForUI::GetDefaultXDisplay();
-    for (std::map<int, Cursor>::iterator it =
-        cache_.begin(); it != cache_.end(); ++it) {
-      XFreeCursor(display, it->second);
-    }
-    cache_.clear();
+    Clear();
   }
 
   Cursor GetCursor(int cursor_shape) {
@@ -134,6 +129,15 @@ class XCursorCache {
     return it.first->second;
   }
 
+  void Clear() {
+    Display* display = base::MessagePumpForUI::GetDefaultXDisplay();
+    for (std::map<int, Cursor>::iterator it =
+        cache_.begin(); it != cache_.end(); ++it) {
+      XFreeCursor(display, it->second);
+    }
+    cache_.clear();
+  }
+
  private:
   // Maps X11 font cursor shapes to Cursor IDs.
   std::map<int, Cursor> cache_;
@@ -218,6 +222,12 @@ int GetDefaultScreen(Display* display) {
 
 Cursor GetXCursor(int cursor_shape) {
   CR_DEFINE_STATIC_LOCAL(XCursorCache, cache, ());
+
+  if (cursor_shape == kCursorClearXCursorCache) {
+    cache.Clear();
+    return 0;
+  }
+
   return cache.GetCursor(cursor_shape);
 }
 
diff --git a/ui/base/x/x11_util.h b/ui/base/x/x11_util.h
index f9e979c..888e76a 100644
--- a/ui/base/x/x11_util.h
+++ b/ui/base/x/x11_util.h
@@ -68,6 +68,10 @@ UI_EXPORT bool QueryRenderSupport(Display* dpy);
 // Return the default screen number for the display
 int GetDefaultScreen(Display* display);
 
+// TODO(xiyuan): Fix the stale XCursorCache problem per http://crbug.com/102759.
+// A special cursor that makes GetXCursor below to clear its XCursorCache.
+const int kCursorClearXCursorCache = -1;
+
 // Returns an X11 Cursor, sharable across the process.
 // |cursor_shape| is an X font cursor shape, see XCreateFontCursor().
 UI_EXPORT Cursor GetXCursor(int cursor_shape);