Re-land: chrome: Add support for use_glib=true to wayland server.

chrome/browser/chrome_browser_main_extra_parts_exo.cc

 // Copyright 2015 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.
 
 #include "chrome/browser/chrome_browser_main_extra_parts_exo.h"
 
+#if defined(USE_GLIB)
+#include <glib.h>
+#endif
+
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "chrome/browser/ui/ash/ash_util.h"
 #include "chrome/common/chrome_switches.h"
 #include "components/exo/display.h"
 #include "components/exo/wayland/server.h"
 #include "content/public/browser/browser_thread.h"
 
+#if defined(USE_GLIB)
+namespace {
+
+struct GLibWaylandSource : public GSource {
+  // Note: The GLibWaylandSource is created and destroyed by GLib. So its
+  // constructor/destructor may or may not get called.
+  exo::wayland::Server* server;
+  GPollFD* poll_fd;
+};
+
+gboolean WaylandSourcePrepare(GSource* source, gint* timeout_ms) {
+  *timeout_ms = -1;
+  return FALSE;
+}
+
+gboolean WaylandSourceCheck(GSource* source) {
+  GLibWaylandSource* wayland_source = static_cast<GLibWaylandSource*>(source);
+  return (wayland_source->poll_fd->revents & G_IO_IN) ? TRUE : FALSE;
+}
+
+gboolean WaylandSourceDispatch(GSource* source,
+                               GSourceFunc unused_func,
+                               gpointer data) {
+  GLibWaylandSource* wayland_source = static_cast<GLibWaylandSource*>(source);
+  wayland_source->server->Dispatch(base::TimeDelta());
+  wayland_source->server->Flush();
+  return TRUE;
+}
+
+GSourceFuncs g_wayland_source_funcs = {WaylandSourcePrepare, WaylandSourceCheck,
+                                       WaylandSourceDispatch, nullptr};
+
+}  // namespace
+
+class ChromeBrowserMainExtraPartsExo::WaylandWatcher {
+ public:
+  explicit WaylandWatcher(exo::wayland::Server* server)
+      : wayland_poll_(new GPollFD),
+        wayland_source_(static_cast<GLibWaylandSource*>(
+            g_source_new(&g_wayland_source_funcs, sizeof(GLibWaylandSource)))) {
+    wayland_poll_->fd = server->GetFileDescriptor();
+    wayland_poll_->events = G_IO_IN;
+    wayland_poll_->revents = 0;
+    wayland_source_->server = server;
+    wayland_source_->poll_fd = wayland_poll_.get();
+    g_source_add_poll(wayland_source_, wayland_poll_.get());
+    g_source_set_can_recurse(wayland_source_, TRUE);
+    g_source_set_callback(wayland_source_, nullptr, nullptr, nullptr);
+    g_source_attach(wayland_source_, g_main_context_default());
+  }
+  ~WaylandWatcher() {
+    g_source_destroy(wayland_source_);
+    g_source_unref(wayland_source_);
+  }
+
+ private:
+  // The poll attached to |wayland_source_|.
+  scoped_ptr<GPollFD> wayland_poll_;
+
+  // The GLib event source for wayland events.
+  GLibWaylandSource* wayland_source_;
+
+  DISALLOW_COPY_AND_ASSIGN(WaylandWatcher);
+};
+#else
 class ChromeBrowserMainExtraPartsExo::WaylandWatcher
     : public base::MessagePumpLibevent::Watcher {
  public:
   explicit WaylandWatcher(exo::wayland::Server* server) : server_(server) {
     base::MessageLoopForUI::current()->WatchFileDescriptor(
         server_->GetFileDescriptor(),
         true,  // persistent
         base::MessagePumpLibevent::WATCH_READ, &controller_, this);
   }
 
   // base::MessagePumpLibevent::Watcher:
   void OnFileCanReadWithoutBlocking(int fd) override {
     server_->Dispatch(base::TimeDelta());
     server_->Flush();
   }
   void OnFileCanWriteWithoutBlocking(int fd) override { NOTREACHED(); }
 
  private:
   base::MessagePumpLibevent::FileDescriptorWatcher controller_;
   exo::wayland::Server* const server_;
 
   DISALLOW_COPY_AND_ASSIGN(WaylandWatcher);
 };
+#endif
 
 ChromeBrowserMainExtraPartsExo::ChromeBrowserMainExtraPartsExo()
     : display_(new exo::Display) {}
 
 ChromeBrowserMainExtraPartsExo::~ChromeBrowserMainExtraPartsExo() {}
 
 void ChromeBrowserMainExtraPartsExo::PreProfileInit() {
   if (!chrome::ShouldOpenAshOnStartup())
     return;
 
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableWaylandServer)) {
     wayland_server_ = exo::wayland::Server::Create(display_.get());
     wayland_watcher_ =
         make_scoped_ptr(new WaylandWatcher(wayland_server_.get()));
   }
 }
 
 void ChromeBrowserMainExtraPartsExo::PostMainMessageLoopRun() {
   wayland_watcher_.reset();
   wayland_server_.reset();
 }