Display Window Icon In Picker UI

chrome/browser/media/window_icon_util_x11.cc

Index: chrome/browser/media/window_icon_util_x11.cc
diff --git a/chrome/browser/media/window_icon_util_x11.cc b/chrome/browser/media/window_icon_util_x11.cc
index 36462dc229d131d6adbc58c1fadb4b26427e3624..b0f65fc16a339cede1696d61c8dcae3df6db2e6f 100644
--- a/chrome/browser/media/window_icon_util_x11.cc
+++ b/chrome/browser/media/window_icon_util_x11.cc
@@ -9,6 +9,15 @@
 
 #include "ui/gfx/x/x11_types.h"
 
+// The error handler is for XGetWindowProperty. Otherwise, XGetWindowProperty
+// may throw an exception, and thus crash Chrome. A possibility is that when
+// GetWindowIcon is called after the window is already closed. Anyway, failure
+// to get an icon is not severe enough to worth blocking the normal workflow or
+// crashing Chrome.
+int ErrorHandler(Display* display, XErrorEvent* event) {
+  return 0;
+}
+
 gfx::ImageSkia GetWindowIcon(content::DesktopMediaID id) {
   DCHECK(id.type == content::DesktopMediaID::TYPE_WINDOW);
 
@@ -20,10 +29,12 @@ gfx::ImageSkia GetWindowIcon(content::DesktopMediaID id) {
   unsigned long size;
   long* data;
 
+  XErrorHandler old_handler = XSetErrorHandler(&ErrorHandler);

[Daniel Erat, 2016/08/25 23:39:58]

please use ui/gfx/x/x11_error_tracker.h instead of writing your own code for
this.

[qiangchen, 2016/08/25 23:54:19]

Done.

   int status = XGetWindowProperty(display, id.id, property, 0L, ~0L, False,
                                   AnyPropertyType, &actual_type, &actual_format,
                                   &size, &bytes_after,
                                   reinterpret_cast<unsigned char**>(&data));
+  XSetErrorHandler(old_handler);
   if (status != Success) {
     return gfx::ImageSkia();
   }