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

Use a debounce timer to get the true window position shortly after the last reconfigure event is delivered, and save that.
BUG=18771
TEST=none

Review URL: http://codereview.chromium.org/203027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@26617 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/gtk/browser_window_gtk.cc

@@ -125,6 +125,10 @@ const int kContentShadowThickness = 2;
 // is off.
 const int kCustomFrameBackgroundVerticalOffset = 15;
 
+// The timeout in milliseconds before we'll get the true window position with
+// gtk_window_get_position() after the last GTK configure-event signal.
+const int kDebounceTimeoutMilliseconds = 100;
+
 base::LazyInstance<ActiveWindowWatcher>
     g_active_window_watcher(base::LINKER_INITIALIZED);
 
@@ -1361,6 +1365,31 @@ void BrowserWindowGtk::OnBoundsChanged(const gfx::Rect& bounds) {
   bounds_ = bounds;
   if (!IsFullscreen() && !IsMaximized())
     restored_bounds_ = bounds;
+
+  // When a window is moved or resized, GTK will call MainWindowConfigured()
+  // above.  The GdkEventConfigure* that it gets 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 (in OnDebouncedBoundsChanged() below) after we haven't seen a
+  // reconfigure event in a short while.
+  // We don't use Reset() because the timer may not yet be running.
+  // (In that case Stop() is a no-op.)
+  window_configure_debounce_timer_.Stop();
+  window_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);
+  if (!IsFullscreen() && !IsMaximized())
+    restored_bounds_.set_origin(origin);
   SaveWindowPosition();
 }
 
@@ -1484,13 +1513,16 @@ void BrowserWindowGtk::SetGeometryHints() {
   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.

chrome/browser/gtk/browser_window_gtk.h

@@ -140,6 +140,7 @@ class BrowserWindowGtk : public BrowserWindow,
   void UpdateUIForContents(TabContents* contents);
 
   void OnBoundsChanged(const gfx::Rect& bounds);
+  void OnDebouncedBoundsChanged();
   void OnStateChanged(GdkWindowState state, GdkWindowState changed_mask);
 
   // Returns false if we're not ready to close yet.  E.g., a tab may have an
@@ -361,6 +362,9 @@ class BrowserWindowGtk : public BrowserWindow,
   // The timer used to update frames for the Loading Animation.
   base::RepeatingTimer<BrowserWindowGtk> loading_animation_timer_;
 
+  // The timer used to save the window position for session restore.
+  base::OneShotTimer<BrowserWindowGtk> window_configure_debounce_timer_;
+
   // Whether the custom chrome frame pref is set.  Normally you want to use
   // UseCustomFrame() above to determine whether to use the custom frame or
   // not.