Fix grabbing capture when the mouse is pressed on Desktop Linux.

ui/base/x/x11_util.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file defines utility functions for X11 (Linux only). This code has been
 // ported from XCB since we can't use XCB on Ubuntu while its 32-bit support
 // remains woefully incomplete.
 
 #include "ui/base/x/x11_util.h"
 
@@ skipping 266 matching lines @@
   std::map< ::Cursor, XCustomCursor*> cache_;
   DISALLOW_COPY_AND_ASSIGN(XCustomCursorCache);
 };
 
 }  // namespace
 
 bool IsXInput2Available() {
   return DeviceDataManagerX11::GetInstance()->IsXInput2Available();
 }
 
+int GrabPointer(XID window, bool owner_events, ::Cursor cursor) {
+  if (IsXInput2Available()) {
+    // Do an XINPUT2 pointer grab. If there is an active XINPUT2 pointer grab
+    // as a result of normal button press, XGrabPointer() will fail.
+    const std::vector<int>& master_pointers =
+        DeviceDataManagerX11::GetInstance()->master_pointers();
+    int success = GrabSuccess;
+    for (size_t i = 0; i < master_pointers.size(); ++i) {
+      unsigned char mask[XIMaskLen(XI_LASTEVENT)];
+      memset(mask, 0, sizeof(mask));
+      XISetMask(mask, XI_ButtonPress);
+      XISetMask(mask, XI_ButtonRelease);
+      XISetMask(mask, XI_Motion);
+      XIEventMask evmask;
+      evmask.deviceid = XIAllDevices;

[sadrul, 2014/12/22 21:08:59]

Should you use master_pointers[i] here?

[pkotwicz, 2014/12/23 00:29:49]

It seems to work either way. I haven't seen any documentation as to which way is
"right".

+      evmask.mask_len = sizeof(mask);
+      evmask.mask = mask;
+      success = XIGrabDevice(gfx::GetXDisplay(), master_pointers[i], window,
+                             CurrentTime, cursor, GrabModeAsync, GrabModeAsync,
+                             owner_events, &evmask);
+      // Assume that the grab will succeed on either all or none of the master
+      // pointers.
+      if (success != GrabSuccess)
+        return success;
+    }
+    return success;
+  } else {

[pkotwicz, 2014/12/01 22:42:48]

Should I try XGrabPointer() if XIGrabDevice() fails?

[sadrul, 2014/12/22 21:08:59]

Sure. Let's try that.

Also, remove else.

[pkotwicz, 2014/12/23 00:29:49]

Done.

+    int event_mask = PointerMotionMask | ButtonReleaseMask | ButtonPressMask;
+    return XGrabPointer(gfx::GetXDisplay(), window, owner_events, event_mask,
+                        GrabModeAsync, GrabModeAsync, None,
+                        cursor, CurrentTime);
+  }
+}
+
+void UngrabPointer() {
+  if (IsXInput2Available()) {
+    const std::vector<int>& master_pointers =
+        DeviceDataManagerX11::GetInstance()->master_pointers();
+    for (size_t i = 0; i < master_pointers.size(); ++i)
+      XIUngrabDevice(gfx::GetXDisplay(), master_pointers[i], CurrentTime);
+  } else {
+    XUngrabPointer(gfx::GetXDisplay(), CurrentTime);
+  }
+}
+
 static SharedMemorySupport DoQuerySharedMemorySupport(XDisplay* dpy) {
   int dummy;
   Bool pixmaps_supported;
   // Query the server's support for XSHM.
   if (!XShmQueryVersion(dpy, &dummy, &dummy, &pixmaps_supported))
     return SHARED_MEMORY_NONE;
 
 #if defined(OS_FREEBSD)
   // On FreeBSD we can't access the shared memory after it was marked for
   // deletion, unless this behaviour is explicitly enabled by the user.
@@ skipping 1198 matching lines @@
       << "request_code " << static_cast<int>(error_event.request_code) << ", "
       << "minor_code " << static_cast<int>(error_event.minor_code)
       << " (" << request_str << ")";
 }
 
 // ----------------------------------------------------------------------------
 // End of x11_util_internal.h
 
 
 }  // namespace ui