Revert broken Linux hidpi changes.

chrome/browser/ui/libgtk2ui/gtk2_ui.cc

Index: chrome/browser/ui/libgtk2ui/gtk2_ui.cc
diff --git a/chrome/browser/ui/libgtk2ui/gtk2_ui.cc b/chrome/browser/ui/libgtk2ui/gtk2_ui.cc
index f9ce890766ce94e9069bcf1ad20e63e448979600..3dbb4d00b36afae33c93c19c7e0810a8a36399e6 100644
--- a/chrome/browser/ui/libgtk2ui/gtk2_ui.cc
+++ b/chrome/browser/ui/libgtk2ui/gtk2_ui.cc
@@ -8,8 +8,6 @@
 #include <set>
 
 #include <pango/pango.h>
-#include <X11/Xlib.h>
-#include <gio/gio.h>
 
 #include "base/command_line.h"
 #include "base/debug/leak_annotations.h"
@@ -384,27 +382,20 @@ gfx::FontRenderParams GetGtkFontRenderParams() {
   return params;
 }
 
-double GetBaseDPI() {
-  XDisplay* xdisplay = gfx::GetXDisplay();
-  int xscreen = DefaultScreen(xdisplay);
-  return (DisplayHeight(xdisplay, xscreen) * 25.4) /
-         DisplayHeightMM(xdisplay, xscreen);
-}
-
-double GetFontDPI() {
+double GetDPI() {
   GtkSettings* gtk_settings = gtk_settings_get_default();
   CHECK(gtk_settings);
   gint gtk_dpi = -1;
   g_object_get(gtk_settings, "gtk-xft-dpi", &gtk_dpi, NULL);
 
   // GTK multiplies the DPI by 1024 before storing it.
-  return (gtk_dpi > 0) ? gtk_dpi / 1024.0 : GetBaseDPI();
+  return (gtk_dpi > 0) ? gtk_dpi / 1024.0 : 96.0;
 }
 
 // Queries GTK for its font DPI setting and returns the number of pixels in a
 // point.
 double GetPixelsInPoint(float device_scale_factor) {
-  double dpi = GetFontDPI();
+  double dpi = GetDPI();
 
   // Take device_scale_factor into account — if Chrome already scales the
   // entire UI up by 2x, we should not also scale up.
@@ -428,21 +419,6 @@ views::LinuxUI::NonClientMiddleClickAction GetDefaultMiddleClickAction() {
   }
 }
 
-double GetGnomeTextScalingFactor() {
-  const char kDesktopInterfaceSchema[] = "org.gnome.desktop.interface";
-  for (const gchar* const* schemas = g_settings_list_schemas(); *schemas;
-       schemas++) {
-    if (!strcmp(kDesktopInterfaceSchema, static_cast<const char*>(*schemas))) {
-      GSettings* settings = g_settings_new(kDesktopInterfaceSchema);
-      double scale = g_settings_get_double(settings, "text-scaling-factor");
-      g_object_unref(settings);
-      return scale;
-    }
-  }
-  // Fallback if the schema does not exist.
-  return GetFontDPI() / GetBaseDPI();
-}
-
 }  // namespace
 
 Gtk2UI::Gtk2UI()
@@ -1462,12 +1438,10 @@ void Gtk2UI::UpdateDeviceScaleFactor(float device_scale_factor) {
 float Gtk2UI::GetDeviceScaleFactor() const {
   if (gfx::Display::HasForceDeviceScaleFactor())
     return gfx::Display::GetForcedDeviceScaleFactor();
-  // Linux chrome does not support dynamnic scale factor change. Use the
-  // value obtanied during startup. The value is rounded to 1 decimal, e.g.
-  // to 1.4, for safety.
-  static float device_scale_factor =
-      roundf(GetGnomeTextScalingFactor() * 10) / 10;
-  return device_scale_factor;
+  const int kCSSDefaultDPI = 96;
+  float scale = GetDPI() / kCSSDefaultDPI;
+  // Round to 2 decimals, e.g. to 1.33.
+  return roundf(scale * 100) / 100;

[stapelberg, 2015/08/07 10:38:22]

I think we should keep the rounding to 1 decimal, i.e.

// Round to 1 decimal, e.g. to 1.4.
return roundf(scale * 10) / 10;

[Michael Moss, 2015/08/07 16:45:40]

Done.

 }
 
 }  // namespace libgtk2ui