Linux: avoid browser windows moving around by the size of WM decorations over restart.

chrome/browser/gtk/browser_window_gtk.cc

 // Copyright (c) 2009 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/gtk/browser_window_gtk.h"
 
 #include <gdk/gdkkeysyms.h>
 #include <X11/XF86keysym.h>
 
 #include <string>
@@ skipping 107 matching lines @@
 // actually a couple pixels more that should overlap the toolbar and web
 // content area, but we don't use those pixels.
 const int kContentShadowThickness = 2;
 // The offset to the background when the custom frame is off.  We want the
 // window background to line up with the tab background regardless of whether
 // we're in custom frame mode or not.  Since themes are designed with the
 // custom frame in mind, we need to offset the background when the custom frame
 // is off.
 const int kCustomFrameBackgroundVerticalOffset = 15;
 
+// When a window is moved or resized, GTK will call MainWindowConfigured below.

[tony, 2009/09/18 18:45:12]

Nit: I expect this comment to either be in the header or near the where we start
the timer.

[Mike Mammarella, 2009/09/18 21:18:40]

Done.

+// The GdkEventConfigure* that we get doesn't have quite the right coordinates
+// though (they're relative to the drawable window area, rather than any window
+// manager decorations, if enabled), so we need to call gtk_window_get_position
+// to get the right values.  (Otherwise session restore, if enabled, will
+// restore windows to incorrect positions.)  That's a round trip to the X server
+// though, so we set a debounce timer and only call it after we haven't seen a
+// reconfigure event in a short while.
+const int kDebounceTimeoutMilliseconds = 100;
+
 base::LazyInstance<ActiveWindowWatcher>
     g_active_window_watcher(base::LINKER_INITIALIZED);
 
 gboolean MainWindowConfigured(GtkWindow* window, GdkEventConfigure* event,
                               BrowserWindowGtk* browser_win) {
   gfx::Rect bounds = gfx::Rect(event->x, event->y, event->width, event->height);
   browser_win->OnBoundsChanged(bounds);
   return FALSE;
 }
 
@@ skipping 1216 matching lines @@
 
 void BrowserWindowGtk::OnBoundsChanged(const gfx::Rect& bounds) {
   GetLocationBar()->location_entry()->ClosePopup();
 
   if (bounds_.size() != bounds.size())
     OnSizeChanged(bounds.width(), bounds.height());
 
   bounds_ = bounds;
   if (!IsFullscreen() && !IsMaximized())
     restored_bounds_ = bounds;
+
+  // We don't use Reset() because the timer may not yet be running.
+  // (In that case Stop() is a no-op.)
+  mainwin_configure_debounce_timer_.Stop();
+  mainwin_configure_debounce_timer_.Start(base::TimeDelta::FromMilliseconds(
+      kDebounceTimeoutMilliseconds), this,
+      &BrowserWindowGtk::OnDebouncedBoundsChanged);
+}
+
+void BrowserWindowGtk::OnDebouncedBoundsChanged() {
+  gint x, y;
+  gtk_window_get_position(window_, &x, &y);
+  gfx::Point origin(x, y);
+  bounds_.set_origin(origin);

[tony, 2009/09/18 18:45:12]

Should we update restored_bounds_ too?

[Mike Mammarella, 2009/09/18 21:18:40]

Done.

   SaveWindowPosition();
 }
 
 void BrowserWindowGtk::OnStateChanged(GdkWindowState state,
                                       GdkWindowState changed_mask) {
   state_ = state;
 
   if (changed_mask & GDK_WINDOW_STATE_FULLSCREEN) {
     bool is_fullscreen = state & GDK_WINDOW_STATE_FULLSCREEN;
     browser_->UpdateCommandsForFullscreenMode(is_fullscreen);
@@ skipping 103 matching lines @@
   geometry.min_height = 1;
   gtk_window_set_geometry_hints(window_, NULL, &geometry, GDK_HINT_MIN_SIZE);
 
   // If we call gtk_window_maximize followed by gtk_window_present, compiz gets
   // confused and maximizes the window, but doesn't set the
   // GDK_WINDOW_STATE_MAXIMIZED bit.  So instead, we keep track of whether to
   // maximize and call it after gtk_window_present.
   maximize_after_show_ = browser_->GetSavedMaximizedState();
 
   gfx::Rect bounds = browser_->GetSavedWindowBounds();
-  // We don't blindly call SetBounds here, that sets a forced position
+  // We don't blindly call SetBounds here: that sets a forced position
   // on the window and we intentionally *don't* do that for normal
-  // windows.  We tested many programs and none of them restored their
-  // position on Linux.
+  // windows.  Most programs do not restore their window position on
+  // Linux, instead letting the window manager choose a position.
   //
   // However, in cases like dropping a tab where the bounds are
-  // specifically set, we do want to position explicitly.
+  // specifically set, we do want to position explicitly.  We also
+  // force the position as part of session restore, as applications
+  // that restore other, similar state (for instance GIMP, audacity,
+  // pidgin, dia, and gkrellm) do tend to restore their positions.
   if (browser_->bounds_overridden()) {
     // For popups, bounds are set in terms of the client area rather than the
     // entire window.
     SetBoundsImpl(bounds, !(browser_->type() & Browser::TYPE_POPUP));
   } else {
     // Ignore the position but obey the size.
     SetWindowSize(window_, bounds.width(), bounds.height());
   }
 }
 
@@ skipping 699 matching lines @@
   // special-case the ones where the custom frame should be used.  These names
   // are taken from the WMs' source code.
   return (wm_name == "Blackbox" ||
           wm_name == "compiz" ||
           wm_name == "e16" ||  // Enlightenment DR16
           wm_name == "KWin" ||
           wm_name == "Metacity" ||
           wm_name == "Openbox" ||
           wm_name == "Xfwm4");
 }