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

ui/base/x/x11_util.h

Index: ui/base/x/x11_util.h
diff --git a/ui/base/x/x11_util.h b/ui/base/x/x11_util.h
index 8cd8bde7a72b93b01e6e8e48ae0f3f53bb8302e0..6568b2a7e6701b4d4522855de5735e968c318135 100644
--- a/ui/base/x/x11_util.h
+++ b/ui/base/x/x11_util.h
@@ -37,6 +37,21 @@ class SkBitmap;
 
 namespace ui {
 
+enum class NetWmMoveResize {

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

nit: add a comment saying that these must match the hardcoded values from ewmh's
_NET_WM_MOVERESIZE spec, and consider explicitly numbering them (or at least
explicitly setting TOPLEFT to 0)

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

Done.

+  SIZE_TOPLEFT,
+  SIZE_TOP,
+  SIZE_TOPRIGHT,
+  SIZE_RIGHT,
+  SIZE_BOTTOMRIGHT,
+  SIZE_BOTTOM,
+  SIZE_BOTTOMLEFT,
+  SIZE_LEFT,
+  MOVE,           // movement only
+  SIZE_KEYBOARD,  // size via keyboard
+  MOVE_KEYBOARD,  // move via keyboard
+  CANCEL,         // cancel operation
+};
+
 // These functions use the default display and this /must/ be called from
 // the UI thread. Thus, they don't support multiple displays.
 
@@ -84,6 +99,12 @@ UI_BASE_X_EXPORT::Cursor CreateInvisibleCursor();
 // Sets whether |window| should use the OS window frame.
 UI_BASE_X_EXPORT void SetUseOSWindowFrame(XID window, bool use_os_window_frame);
 
+// Requests the window manager move or resize the window on behalf of Chromium.
+// Clients MUST release all grabs prior to calling.

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

maybe document that this isn't implemented by all window managers (perhaps
explicitly calling out tiling ones) and that the caller should check for support
first.

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

Done.

+UI_BASE_X_EXPORT void MoveResizeWindowManaged(XID window,

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

nit: change "WindowManaged" to "ManagedWindow"?

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

Done.

+                                              gfx::Point origin,

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

per the spec, this is actually the pointer position relative to the root
window's origin at the start of the operation, right? if that's correct, please
name it something like |event_root| and document it in the comment.

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

Done.

+                                              NetWmMoveResize mode);
+
 // These functions do not cache their results --------------------------
 
 // Returns true if the shape extension is supported.