Support GrabWindowSnapshot with no g_browser_process

chrome/browser/ui/window_snapshot/window_snapshot.h

Index: chrome/browser/ui/window_snapshot/window_snapshot.h
diff --git a/chrome/browser/ui/window_snapshot/window_snapshot.h b/chrome/browser/ui/window_snapshot/window_snapshot.h
index bad52012aefd21c6f7ae39856540e8154468b70a..2147492f5ec87ae038b9b27b78754dacc451e158 100644
--- a/chrome/browser/ui/window_snapshot/window_snapshot.h
+++ b/chrome/browser/ui/window_snapshot/window_snapshot.h
@@ -20,7 +20,11 @@ namespace chrome {
 // Grabs a snapshot of the rectangle area |snapshot_bounds| with respect to the
 // top left corner of the designated window and stores a PNG representation
 // into a byte vector. On Windows, |window| may be NULL to grab a snapshot of
-// the primary monitor. Returns true if the operation is successful.
+// the primary monitor. This checks policy settings if taking screenshots is
+// allowed, and is intended to by used by browser code. If you need to take a
+// screenshot for debugging purposes, use ui::GrabWindowSnapshot
+// (ui/window_snapshot/window_snapshot.h).
+// Returns true if the operation is successful (ie. permitted).
 bool GrabWindowSnapshot(
     gfx::NativeWindow window,
     std::vector<unsigned char>* png_representation,