Change snasphotting API to take in a bounds Rect

chrome/browser/ui/window_snapshot/window_snapshot_gtk.cc

Index: chrome/browser/ui/window_snapshot/window_snapshot_gtk.cc
diff --git a/chrome/browser/ui/window_snapshot/window_snapshot_gtk.cc b/chrome/browser/ui/window_snapshot/window_snapshot_gtk.cc
index 4507996ad5264b6ab7102f84d2648e8b98d2de3a..a0eb05a2853b1a9795c3a2964567dcead04f2b7e 100644
--- a/chrome/browser/ui/window_snapshot/window_snapshot_gtk.cc
+++ b/chrome/browser/ui/window_snapshot/window_snapshot_gtk.cc
@@ -25,7 +25,8 @@ static cairo_status_t SnapshotCallback(
 }
 
 gfx::Rect GrabWindowSnapshot(gfx::NativeWindow gtk_window,
-                             std::vector<unsigned char>* png_representation) {
+                             std::vector<unsigned char>* png_representation,
+                             gfx::Rect snapshot_bounds) {
   GdkWindow* gdk_window = GTK_WIDGET(gtk_window)->window;
   Display* display = GDK_WINDOW_XDISPLAY(gdk_window);
   XID win = GDK_WINDOW_XID(gdk_window);
@@ -34,8 +35,17 @@ gfx::Rect GrabWindowSnapshot(gfx::NativeWindow gtk_window,
     LOG(ERROR) << "Couldn't get window attributes";
     return gfx::Rect();
   }
+
+  if (snapshot_bounds.IsEmpty()) {
+    snapshot_bounds = gfx::Rect(0, 0, attr.width, attr.height);
+  }
+
+  DCHECK(snapshot_bounds.right() <= attr.width);
+  DCHECK(snapshot_bounds.bottom() <= attr.height);
+
   XImage* image = XGetImage(
-      display, win, 0, 0, attr.width, attr.height, AllPlanes, ZPixmap);
+      display, win, snapshot_bounds.x(), snapshot_bounds.y(),
+      snapshot_bounds.width(), snapshot_bounds.height(), AllPlanes, ZPixmap);
   if (!image) {
     LOG(ERROR) << "Couldn't get image";
     return gfx::Rect();