Linux Aura: Use managed tab dragging when possible (Reland)

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 ec6b5363d72403d266c487e9e625a49ff7751e1d..01ce47bce67162b3d525e7ed267bf16352d9d134 100644
--- a/ui/base/x/x11_util.cc
+++ b/ui/base/x/x11_util.cc
@@ -495,6 +495,30 @@ void SetUseOSWindowFrame(XID window, bool use_os_window_frame) {
                   sizeof(MotifWmHints)/sizeof(long));
 }
 
+void MoveResizeWindowManaged(XID window,
+                             gfx::Point origin,
+                             NetWmMoveResize mode) {
+  XDisplay* display = gfx::GetXDisplay();
+  XAtom message_type = GetAtom("_NET_WM_MOVERESIZE");
+  XEvent event;
+  memset(&event, 0, sizeof(event));
+  event.xclient.type = ClientMessage;
+  event.xclient.display = display;
+  event.xclient.window = window;
+  event.xclient.message_type = message_type;
+  event.xclient.format = 32;
+  event.xclient.data.l[0] = origin.x();
+  event.xclient.data.l[1] = origin.y();
+  event.xclient.data.l[2] = static_cast<long>(mode);
+  event.xclient.data.l[3] =
+      Button1;  // Currently all our managed dragging is done with LMB.
+  event.xclient.data.l[4] = 1;

[Daniel Erat, 2016/10/12 16:13:10]

nit: add something like "// Requested by normal application" at the end of this
line

[Tom (Use chromium acct), 2016/10/12 18:08:27]

Done.

+
+  XSendEvent(display, DefaultRootWindow(display), False,
+             SubstructureRedirectMask | SubstructureNotifyMask, &event);
+  XFlush(display);
+}
+
 bool IsShapeExtensionAvailable() {
   int dummy;
   static bool is_shape_available =