linux aura: Fix window activation in some X11 window managers.

ui/views/widget/desktop_aura/x11_desktop_handler.cc

Index: ui/views/widget/desktop_aura/x11_desktop_handler.cc
diff --git a/ui/views/widget/desktop_aura/x11_desktop_handler.cc b/ui/views/widget/desktop_aura/x11_desktop_handler.cc
index 179bc759a171c2f4c0cf5cd0b0e9bf1062286be9..e29ce9c03c1d273d23c1fa2c31d6155eb045b1c5 100644
--- a/ui/views/widget/desktop_aura/x11_desktop_handler.cc
+++ b/ui/views/widget/desktop_aura/x11_desktop_handler.cc
@@ -4,6 +4,9 @@
 
 #include "ui/views/widget/desktop_aura/x11_desktop_handler.h"
 
+#include <X11/Xatom.h>
+#include <X11/Xlib.h>
+
 #include "base/message_loop/message_loop.h"
 #include "ui/aura/env.h"
 #include "ui/aura/root_window.h"
@@ -18,6 +21,7 @@ namespace {
 
 const char* kAtomsToCache[] = {
   "_NET_ACTIVE_WINDOW",
+  "_NET_SUPPORTED",
   NULL
 };
 
@@ -40,7 +44,8 @@ X11DesktopHandler::X11DesktopHandler()
     : xdisplay_(gfx::GetXDisplay()),
       x_root_window_(DefaultRootWindow(xdisplay_)),
       current_window_(None),
-      atom_cache_(xdisplay_, kAtomsToCache) {
+      atom_cache_(xdisplay_, kAtomsToCache),
+      wm_supports_active_window_(false) {
   base::MessagePumpX11::Current()->AddDispatcherForRootWindow(this);
   aura::Env::GetInstance()->AddObserver(this);
 
@@ -49,6 +54,28 @@ X11DesktopHandler::X11DesktopHandler()
   XSelectInput(xdisplay_, x_root_window_,
                attr.your_event_mask | PropertyChangeMask |
                StructureNotifyMask | SubstructureNotifyMask);
+
+  const int kMaxWMAtoms = 64;
+  size_t atoms_count = 0;
+  Atom* atoms = NULL;
+  Atom type;
+  int format;
+  size_t bytes;
+  XGetWindowProperty(xdisplay_, x_root_window_,
+                     atom_cache_.GetAtom("_NET_SUPPORTED"),
+                     0, kMaxWMAtoms,
+                     False, XA_ATOM,
+                     &type, &format, &atoms_count, &bytes,
+                     reinterpret_cast<unsigned char**>(&atoms));

[Elliot Glaysher, 2013/11/14 18:37:38]

ui::GetAtomArrayProperty()?

[sadrul, 2013/11/14 19:06:41]

Done.

+  if (type == XA_ATOM) {
+    Atom active_window = atom_cache_.GetAtom("_NET_ACTIVE_WINDOW");
+    for (size_t i = 0; i < atoms_count; ++i) {
+      if (atoms[i] == active_window) {
+        wm_supports_active_window_ = true;
+        break;
+      }
+    }
+  }
 }
 
 X11DesktopHandler::~X11DesktopHandler() {
@@ -57,23 +84,28 @@ X11DesktopHandler::~X11DesktopHandler() {
 }
 
 void X11DesktopHandler::ActivateWindow(::Window window) {
-  DCHECK_EQ(gfx::GetXDisplay(), xdisplay_);
-
-  XEvent xclient;
-  memset(&xclient, 0, sizeof(xclient));
-  xclient.type = ClientMessage;
-  xclient.xclient.window = window;
-  xclient.xclient.message_type = atom_cache_.GetAtom("_NET_ACTIVE_WINDOW");
-  xclient.xclient.format = 32;
-  xclient.xclient.data.l[0] = 1;  // Specified we are an app.
-  xclient.xclient.data.l[1] = CurrentTime;
-  xclient.xclient.data.l[2] = None;
-  xclient.xclient.data.l[3] = 0;
-  xclient.xclient.data.l[4] = 0;
-
-  XSendEvent(xdisplay_, x_root_window_, False,
-             SubstructureRedirectMask | SubstructureNotifyMask,
-             &xclient);
+  if (wm_supports_active_window_) {
+    DCHECK_EQ(gfx::GetXDisplay(), xdisplay_);
+
+    XClientMessageEvent xclient;

[Elliot Glaysher, 2013/11/14 18:37:38]

piman would disprove. He's told me several times to specify the toplevel type.

[sadrul, 2013/11/14 19:06:41]

Reverted (I hadn't meant to include this in the CL)

+    memset(&xclient, 0, sizeof(xclient));
+    xclient.type = ClientMessage;
+    xclient.window = window;
+    xclient.message_type = atom_cache_.GetAtom("_NET_ACTIVE_WINDOW");
+    xclient.format = 32;
+    xclient.data.l[0] = 1;  // Specified we are an app.
+    xclient.data.l[1] = CurrentTime;
+    xclient.data.l[2] = None;
+    xclient.data.l[3] = 0;
+    xclient.data.l[4] = 0;
+
+    XSendEvent(xdisplay_, x_root_window_, False,
+               SubstructureRedirectMask | SubstructureNotifyMask,
+               (XEvent*)&xclient);
+  } else {
+    XRaiseWindow(xdisplay_, window);
+    OnActiveWindowChanged(window);
+  }
 }
 
 bool X11DesktopHandler::IsActiveWindow(::Window window) const {