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

The X specification allows the OS to grab the mouse when a mouse button is
pressed. The OS grab was causing XGrabPointer() in
DesktopWindowTreeHostX11::SetCapture() to fail.

BUG=426380
TEST=Manual

Review URL: https://codereview.chromium.org/749063003

Cr-Commit-Position: refs/heads/master@{#314501}

4 files changed, 59 insertions, 4 deletions

diff --git a/ui/events/devices/x11/device_data_manager_x11.cc b/ui/events/devices/x11/device_data_manager_x11.cc
index 68fdb2c..85c697a 100644
--- a/ui/events/devices/x11/device_data_manager_x11.cc
+++ b/ui/events/devices/x11/device_data_manager_x11.cc
@@ -202,6 +202,7 @@ bool DeviceDataManagerX11::IsXInput2Available() const {
 void DeviceDataManagerX11::UpdateDeviceList(Display* display) {
   cmt_devices_.reset();
   touchpads_.reset();
+  master_pointers_.clear();
   for (int i = 0; i < kMaxDeviceNum; ++i) {
     valuator_count_[i] = 0;
     valuator_lookup_[i].clear();
@@ -233,6 +234,9 @@ void DeviceDataManagerX11::UpdateDeviceList(Display* display) {
   for (int i = 0; i < info_list.count; ++i) {
     XIDeviceInfo* info = info_list.devices + i;
 
+    if (info->use == XIMasterPointer)
+      master_pointers_.push_back(info->deviceid);
+
     // We currently handle only slave, non-keyboard devices
     if (info->use != XISlavePointer && info->use != XIFloatingSlave)
       continue;
diff --git a/ui/events/devices/x11/device_data_manager_x11.h b/ui/events/devices/x11/device_data_manager_x11.h
index ec580cb..bb5fa15 100644
--- a/ui/events/devices/x11/device_data_manager_x11.h
+++ b/ui/events/devices/x11/device_data_manager_x11.h
@@ -239,6 +239,10 @@ class EVENTS_DEVICES_EXPORT DeviceDataManagerX11 : public DeviceDataManager {
   // Returns true if |native_event| should be blocked.
   bool IsEventBlocked(const base::NativeEvent& native_event);
 
+  const std::vector<int>& master_pointers() const {
+    return master_pointers_;
+  }
+
  protected:
   // DeviceHotplugEventObserver:
   void OnKeyboardDevicesUpdated(
@@ -274,6 +278,9 @@ class EVENTS_DEVICES_EXPORT DeviceDataManagerX11 : public DeviceDataManager {
   std::bitset<kMaxDeviceNum> cmt_devices_;
   std::bitset<kMaxDeviceNum> touchpads_;
 
+  // List of the master pointer devices.
+  std::vector<int> master_pointers_;
+
   // A quick lookup table for determining if events from the XI device
   // should be blocked.
   std::bitset<kMaxDeviceNum> blocked_devices_;
diff --git a/ui/events/devices/x11/touch_factory_x11.cc b/ui/events/devices/x11/touch_factory_x11.cc
index 929c595..4201fa0 100644
--- a/ui/events/devices/x11/touch_factory_x11.cc
+++ b/ui/events/devices/x11/touch_factory_x11.cc
@@ -201,6 +201,8 @@ void TouchFactory::SetupXI2ForXWindow(Window window) {
   XISetMask(mask, XI_ButtonRelease);
   XISetMask(mask, XI_Motion);
 #if defined(OS_CHROMEOS)
+  // XGrabKey() must be replaced with XI2 keyboard grab if XI2 key events are
+  // enabled on desktop Linux.
   if (base::SysInfo::IsRunningOnChromeOS()) {
     XISetMask(mask, XI_KeyPress);
     XISetMask(mask, XI_KeyRelease);
diff --git a/ui/views/widget/desktop_aura/x11_pointer_grab.cc b/ui/views/widget/desktop_aura/x11_pointer_grab.cc
index 1354159..26a1c1d 100644
--- a/ui/views/widget/desktop_aura/x11_pointer_grab.cc
+++ b/ui/views/widget/desktop_aura/x11_pointer_grab.cc
@@ -3,8 +3,11 @@
 // found in the LICENSE file.
 
 #include "base/logging.h"
+#include "ui/base/x/x11_util.h"
+#include "ui/events/devices/x11/device_data_manager_x11.h"
 #include "ui/views/widget/desktop_aura/x11_pointer_grab.h"
 
+#include <X11/extensions/XInput2.h>
 #include <X11/Xlib.h>
 
 namespace views {
@@ -20,10 +23,42 @@ bool g_owner_events = false;
 }  // namespace
 
 int GrabPointer(XID window, bool owner_events, ::Cursor cursor) {
-  int event_mask = PointerMotionMask | ButtonReleaseMask | ButtonPressMask;
-  int result = XGrabPointer(gfx::GetXDisplay(), window, owner_events,
-                            event_mask, GrabModeAsync, GrabModeAsync, None,
-                            cursor, CurrentTime);
+  int result = GrabInvalidTime;
+  if (ui::IsXInput2Available()) {
+    // Do an XInput2 pointer grab. If there is an active XInput2 pointer grab
+    // as a result of normal button press, XGrabPointer() will fail.
+    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.mask_len = sizeof(mask);
+    evmask.mask = mask;
+
+    const std::vector<int>& master_pointers =
+        ui::DeviceDataManagerX11::GetInstance()->master_pointers();
+    for (int master_pointer : master_pointers) {
+      evmask.deviceid = master_pointer;
+      result = XIGrabDevice(
+          gfx::GetXDisplay(), master_pointer, window, CurrentTime, cursor,
+          GrabModeAsync, GrabModeAsync, owner_events, &evmask);
+      // Assume that the grab will succeed on either all or none of the master
+      // pointers.
+      if (result != GrabSuccess) {
+        // Try core pointer grab.
+        break;
+      }
+    }
+  }
+
+  if (result != GrabSuccess) {
+    int event_mask = PointerMotionMask | ButtonReleaseMask | ButtonPressMask;
+    result =
+        XGrabPointer(gfx::GetXDisplay(), window, owner_events, event_mask,
+                     GrabModeAsync, GrabModeAsync, None, cursor, CurrentTime);
+  }
+
   if (result == GrabSuccess) {
     g_grab_window = window;
     g_owner_events = owner_events;
@@ -38,6 +73,13 @@ void ChangeActivePointerGrabCursor(::Cursor cursor) {
 
 void UngrabPointer() {
   g_grab_window = None;
+  if (ui::IsXInput2Available()) {
+    const std::vector<int>& master_pointers =
+        ui::DeviceDataManagerX11::GetInstance()->master_pointers();
+    for (int master_pointer : master_pointers)
+      XIUngrabDevice(gfx::GetXDisplay(), master_pointer, CurrentTime);
+  }
+  // Try core pointer ungrab in case the XInput2 pointer ungrab failed.
   XUngrabPointer(gfx::GetXDisplay(), CurrentTime);
 }