Window capture stop draw cursor when it points to the hidden content.

content/browser/media/capture/aura_window_capture_machine.cc

Index: content/browser/media/capture/aura_window_capture_machine.cc
diff --git a/content/browser/media/capture/aura_window_capture_machine.cc b/content/browser/media/capture/aura_window_capture_machine.cc
index 9d2de8880746d9a3d29d56c2d791c391f5264d2f..334477fd541b647136910db4007b0cccc812afbe 100644
--- a/content/browser/media/capture/aura_window_capture_machine.cc
+++ b/content/browser/media/capture/aura_window_capture_machine.cc
@@ -30,6 +30,7 @@
 #include "ui/compositor/dip_util.h"
 #include "ui/compositor/layer.h"
 #include "ui/gfx/screen.h"
+#include "ui/wm/public/activation_client.h"
 
 namespace content {
 
@@ -413,6 +414,19 @@ gfx::Point AuraWindowCaptureMachine::UpdateCursorState(
     return gfx::Point();
   }
 
+  // Return early if the target content pointed by the mouse is hidden.
+  aura::client::ActivationClient* activation_client =
+      aura::client::GetActivationClient(desktop_window_->GetRootWindow());
+  DCHECK(activation_client);
+  aura::Window* active_window = activation_client->GetActiveWindow();
+  DCHECK(active_window);
+  if (active_window != desktop_window_) {
+    if (active_window->GetBoundsInScreen().Contains(cursor_position)) {

[miu, 2015/10/19 19:49:47]

This mostly works.  It wouldn't if there were TWO windows on top of the window
being mirrored.  ;-)

However, I think you're on the right track here.  IMO, it would be reasonable to
simply shut off the cursor if the mirrored window is not the currently-active
window (or a parent of it).  Meaning, just do:

  if (!desktop_window_->Contains(active_window)) {
    ClearCursorState();
    return gfx::Point();
  }

BTW--After doing this, you don't need the DCHECK(active_window) statement since
the Window::Contains() will safely handle null pointers.

[xjz, 2015/10/20 00:03:21]

Done.

+      ClearCursorState();
+      return gfx::Point();
+    }
+  }
+
   gfx::NativeCursor cursor = desktop_window_->GetHost()->last_cursor();
   gfx::Point cursor_hot_point;
   if (last_cursor_ != cursor ||