Add support for WM_NCPOINTER* messages.

A recent change caused the caption buttons to stop responding to touch.
When I investigated, the change caused Windows to send WM_NCPOINTERDOWN
and WM_NCPOINTERUP in that area (which we don't handle), where
previously it was sending WM_POINTERDOWN and WM_POINTERUP.

Since the change in question is fixing a different critical issue, this
patch implements handling for WM_NCPOINTERDOWN, WM_NCPOINTERUP, and
WM_NCPOINTERUPDATE, by delegating to the existing touch event handler.

This patch also modifies the workaround frin crrev.com/c/1260507, since
the type of messages being translated into ui::ET_TOUCH_RELEASED events
is now different.

Bug: 897662
Change-Id: I6fd052211b91a9a78834573deac830883972092b
Reviewed-on: https://chromium-review.googlesource.com/c/1330838Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608108}

ui/views/win/hwnd_message_handler.cc

@@ -2950,7 +2950,7 @@ LRESULT HWNDMessageHandler::HandlePointerEventTypeTouch(UINT message,
 
   // Increment |touch_down_contexts_| on a pointer down. This variable
   // is used to debounce the WM_MOUSEACTIVATE events.
-  if (message == WM_POINTERDOWN) {
+  if (message == WM_POINTERDOWN || message == WM_NCPOINTERDOWN) {
     touch_down_contexts_++;
     base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
         FROM_HERE,
@@ -3004,10 +3004,24 @@ LRESULT HWNDMessageHandler::HandlePointerEventTypeTouch(UINT message,
     if (event_type == ui::ET_TOUCH_RELEASED)
       id_generator_.ReleaseNumber(pointer_id);
 
-    // Mark all touch released events handled. These will usually turn into tap
+    // Mark touch released events handled. These will usually turn into tap
     // gestures, and doing this avoids propagating the event to other windows.
-    const bool always_mark_handled = event_type == ui::ET_TOUCH_RELEASED;
-    SetMsgHandled(always_mark_handled || event.handled());
+    if (delegate_->GetFrameMode() == FrameMode::SYSTEM_DRAWN) {
+      // WM_NCPOINTERUP must be DefWindowProc'ed in order for the system caption
+      // buttons to work correctly.
+      if (message == WM_POINTERUP)
+        event.SetHandled();
+    } else {
+      // Messages on HTCAPTION should be DefWindowProc'ed, as we let Windows
+      // take care of dragging the window and double-tapping to maximize.
+      const bool on_titlebar =
+          SendMessage(hwnd(), WM_NCHITTEST, 0, l_param) == HTCAPTION;
+      // Unlike above, we must mark both WM_POINTERUP and WM_NCPOINTERUP as
+      // handled, in order for the custom caption buttons to work correctly.
+      if (event_type == ui::ET_TOUCH_RELEASED && !on_titlebar)
+        event.SetHandled();
+    }
+    SetMsgHandled(event.handled());
   }
   return 0;
 }

ui/views/win/hwnd_message_handler.h

@@ -355,6 +355,9 @@ class VIEWS_EXPORT HWNDMessageHandler : public gfx::WindowImpl,
     CR_MESSAGE_HANDLER_EX(WM_POINTERUPDATE, OnPointerEvent)
     CR_MESSAGE_HANDLER_EX(WM_POINTERENTER, OnPointerEvent)
     CR_MESSAGE_HANDLER_EX(WM_POINTERLEAVE, OnPointerEvent)
+    CR_MESSAGE_HANDLER_EX(WM_NCPOINTERDOWN, OnPointerEvent)
+    CR_MESSAGE_HANDLER_EX(WM_NCPOINTERUP, OnPointerEvent)
+    CR_MESSAGE_HANDLER_EX(WM_NCPOINTERUPDATE, OnPointerEvent)
 
     // Key events.
     CR_MESSAGE_HANDLER_EX(WM_KEYDOWN, OnKeyEvent)

ui/views/win/pen_event_processor.cc

@@ -48,7 +48,7 @@ std::unique_ptr<ui::Event> PenEventProcessor::GenerateEvent(
     DCHECK(!eraser_pointer_id_ || *eraser_pointer_id_ == mapped_pointer_id);
     eraser_pointer_id_ = mapped_pointer_id;
   } else if (eraser_pointer_id_ && *eraser_pointer_id_ == mapped_pointer_id &&
-             message == WM_POINTERUP) {
+             (message == WM_POINTERUP || message == WM_NCPOINTERUP)) {
     input_type = ui::EventPointerType::POINTER_TYPE_ERASER;
     eraser_pointer_id_.reset();
   }
@@ -113,6 +113,7 @@ std::unique_ptr<ui::Event> PenEventProcessor::GenerateMouseEvent(
   int click_count = 0;
   switch (message) {
     case WM_POINTERDOWN:
+    case WM_NCPOINTERDOWN:
       event_type = ui::ET_MOUSE_PRESSED;
       if (pointer_info.ButtonChangeType == POINTER_CHANGE_FIRSTBUTTON_DOWN)
         changed_flag = ui::EF_LEFT_MOUSE_BUTTON;
@@ -122,6 +123,7 @@ std::unique_ptr<ui::Event> PenEventProcessor::GenerateMouseEvent(
       sent_mouse_down_ = true;
       break;
     case WM_POINTERUP:
+    case WM_NCPOINTERUP:
       event_type = ui::ET_MOUSE_RELEASED;
       if (pointer_info.ButtonChangeType == POINTER_CHANGE_FIRSTBUTTON_UP) {
         flag |= ui::EF_LEFT_MOUSE_BUTTON;
@@ -137,6 +139,7 @@ std::unique_ptr<ui::Event> PenEventProcessor::GenerateMouseEvent(
       sent_mouse_down_ = false;
       break;
     case WM_POINTERUPDATE:
+    case WM_NCPOINTERUPDATE:
       event_type = ui::ET_MOUSE_DRAGGED;
       if (flag == ui::EF_NONE)
         event_type = ui::ET_MOUSE_MOVED;
@@ -169,10 +172,12 @@ std::unique_ptr<ui::Event> PenEventProcessor::GenerateTouchEvent(
   ui::EventType event_type = ui::ET_TOUCH_MOVED;
   switch (message) {
     case WM_POINTERDOWN:
+    case WM_NCPOINTERDOWN:
       event_type = ui::ET_TOUCH_PRESSED;
       sent_touch_start_ = true;
       break;
     case WM_POINTERUP:
+    case WM_NCPOINTERUP:
       event_type = ui::ET_TOUCH_RELEASED;
       id_generator_->ReleaseNumber(pointer_id);
       if (!sent_touch_start_)
@@ -180,6 +185,7 @@ std::unique_ptr<ui::Event> PenEventProcessor::GenerateTouchEvent(
       sent_touch_start_ = false;
       break;
     case WM_POINTERUPDATE:
+    case WM_NCPOINTERUPDATE:
       event_type = ui::ET_TOUCH_MOVED;
       break;
     default: