[PointerLock] Move "silent mouse lock" logic from renderer to RWHI

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 610567e43a9f72e1ced93032dc903e0581b9a79c..12eaaf87d3feabad565849d2def274b44419d49a 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -286,6 +286,7 @@ RenderWidgetHostImpl::RenderWidgetHostImpl(RenderWidgetHostDelegate* delegate,
       suppress_events_until_keydown_(false),
       pending_mouse_lock_request_(false),
       allow_privileged_mouse_lock_(false),
+      is_last_unlocked_by_target_(false),
       has_touch_handler_(false),
       is_in_touchpad_gesture_fling_(false),
       latency_tracker_(),
@@ -2068,7 +2069,6 @@ void RenderWidgetHostImpl::OnImeCancelComposition() {
 }
 
 void RenderWidgetHostImpl::OnLockMouse(bool user_gesture,
-                                       bool last_unlocked_by_target,
                                        bool privileged) {
   if (pending_mouse_lock_request_) {
     Send(new ViewMsg_LockMouse_ACK(routing_id_, false));
@@ -2077,8 +2077,12 @@ void RenderWidgetHostImpl::OnLockMouse(bool user_gesture,
 
   pending_mouse_lock_request_ = true;
   if (delegate_) {
-    delegate_->RequestToLockMouse(this, user_gesture, last_unlocked_by_target,
+    delegate_->RequestToLockMouse(this, user_gesture,
+                                  is_last_unlocked_by_target_,
                                   privileged && allow_privileged_mouse_lock_);
+    // We need to reset |is_last_unlocked_by_target_| here as we don't know
+    // request source in |LostMouseLock()|.
+    is_last_unlocked_by_target_ = false;
     return;
   }
 
@@ -2092,7 +2096,12 @@ void RenderWidgetHostImpl::OnLockMouse(bool user_gesture,
 }
 
 void RenderWidgetHostImpl::OnUnlockMouse() {
-  RejectMouseLockOrUnlockIfNecessary();
+  if (!pending_mouse_lock_request_ && IsMouseLocked()) {
+    // Got unlock request from renderer. Otherwise we only got |LostMouseLock()|
+    // if user unlocked mouse by pressing ESC.
+    is_last_unlocked_by_target_ = true;
+    view_->UnlockMouse();
+  }

[chongz, 2017/06/01 14:58:20]

Actually I don't think we should use |RejectMouseLockOrUnlockIfNecessary()|
here. |RejectMouseLockOrUnlockIfNecessary()| might 1. Reject lock request, or 2.
Automatically unlock mouse, which should only be used on destruction.

Moved unlock logic here instead of passing the boolean bit.

[dtapuska, 2017/06/05 14:49:49]

This pending_mouse_lock_request boolean is a little odd since it appears to all
be synchronous. Is this possibly some dead code that we might be able to get rid
of? See
https://chromium.googlesource.com/chromium/src/+/b6adb5143ab0cc79a64c64a42f96...

Maybe we can just change the RequestToLockMouse to actually be a boolean return
value?

[chongz, 2017/06/05 15:33:57]

Added back |RejectMouseLockOrUnlockIfNecessary()| as per our offline discussion.
We could set |is_last_unlocked_by_target_ = true;| before calling
|RejectMouseLockOrUnlockIfNecessary()|, but I'm feeling doing it after would
make the code easier to reason about.

Filed crbug.com/729584 to track the cleanup.

 }
 
 void RenderWidgetHostImpl::OnShowDisambiguationPopup(