Fix ui_controls::SendMouseEvents* on Win10 Fall Creators Update.

A change in Windows made absolute moves to coordinate 0,0 not work. It
seems that moving to 1,1 (normalized) does the trick. 1,1 will round
down to 0,0 for any display we care about.

BUG=827549

Change-Id: I76fac0313901ba68bb35ed624c475aed23592029
Reviewed-on: https://chromium-review.googlesource.com/1004734Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Greg Thompson <grt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549639}

chrome/browser/ui/send_mouse_move_uitest_win.cc

@@ -56,9 +56,8 @@ IN_PROC_BROWSER_TEST_F(SendMouseMoveUITest, DISABLED_Fullscreen) {
   }
 }
 
-// (crbug.com/827549): Flaky on Win10 bots.
 // Test that the mouse can be positioned at a few locations on the screen.
-IN_PROC_BROWSER_TEST_F(SendMouseMoveUITest, DISABLED_Probe) {
+IN_PROC_BROWSER_TEST_F(SendMouseMoveUITest, Probe) {
   // Make the browser fullscreen so that we can position the mouse anywhere on
   // the display, as ui_controls::SendMouseMoveNotifyWhenDone can only provide
   // notifications when the mouse is moved over a window belonging to the

ui/base/test/ui_controls_internal_win.cc

@@ -4,7 +4,9 @@
 
 #include "ui/base/test/ui_controls_internal_win.h"
 
+#include <algorithm>
 #include <cmath>
+#include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ -75,9 +77,11 @@ class InputDispatcher : public base::RefCounted<InputDispatcher> {
   // Callback from hook when a key message is received.
   static LRESULT CALLBACK KeyHook(int n_code, WPARAM w_param, LPARAM l_param);
 
-  // Invoked from the hook. If mouse_message matches message_waiting_for_
-  // MatchingMessageFound is invoked.
-  void DispatchedMessage(WPARAM mouse_message);
+  // Invoked from the hook. If |message_id| matches message_waiting_for_
+  // MatchingMessageFound is invoked. |mouse_hook_struct| contains extra
+  // information about the mouse event.
+  void DispatchedMessage(UINT message_id,
+                         const MOUSEHOOKSTRUCT* mouse_hook_struct);
 
   // Invoked when a matching event is found. Uninstalls the hook and schedules
   // an event that runs the callback.
@@ -196,7 +200,8 @@ LRESULT CALLBACK InputDispatcher::MouseHook(int n_code,
   HHOOK next_hook = next_hook_;
   if (n_code == HC_ACTION) {
     DCHECK(current_dispatcher_);
-    current_dispatcher_->DispatchedMessage(w_param);
+    current_dispatcher_->DispatchedMessage(
+        w_param, reinterpret_cast<MOUSEHOOKSTRUCT*>(l_param));
   }
   return CallNextHookEx(next_hook, n_code, w_param, l_param);
 }
@@ -216,26 +221,28 @@ LRESULT CALLBACK InputDispatcher::KeyHook(int n_code,
   return CallNextHookEx(next_hook, n_code, w_param, l_param);
 }
 
-void InputDispatcher::DispatchedMessage(WPARAM mouse_message) {
+void InputDispatcher::DispatchedMessage(
+    UINT message_id,
+    const MOUSEHOOKSTRUCT* mouse_hook_struct) {
   DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
-  if (mouse_message == message_waiting_for_) {
-    if (mouse_message == WM_MOUSEMOVE) {
+  if (message_id == message_waiting_for_) {
+    if (message_id == WM_MOUSEMOVE) {
       // Verify that the mouse ended up at the desired location.
-      POINT current_pos;
-      ::GetCursorPos(&current_pos);
-      LOG_IF(ERROR, expected_mouse_location_ != gfx::Point(current_pos))
-          << "Mouse moved to (" << current_pos.x << ", " << current_pos.y
-          << ") rather than (" << expected_mouse_location_.x() << ", "
+      LOG_IF(ERROR,
+             expected_mouse_location_ != gfx::Point(mouse_hook_struct->pt))
+          << "Mouse moved to (" << mouse_hook_struct->pt.x << ", "
+          << mouse_hook_struct->pt.y << ") rather than ("
+          << expected_mouse_location_.x() << ", "
           << expected_mouse_location_.y()
           << "); check the math in SendMouseMoveImpl.";
     }
     MatchingMessageFound();
   } else if ((message_waiting_for_ == WM_LBUTTONDOWN &&
-              mouse_message == WM_LBUTTONDBLCLK) ||
+              message_id == WM_LBUTTONDBLCLK) ||
              (message_waiting_for_ == WM_MBUTTONDOWN &&
-              mouse_message == WM_MBUTTONDBLCLK) ||
+              message_id == WM_MBUTTONDBLCLK) ||
              (message_waiting_for_ == WM_RBUTTONDOWN &&
-              mouse_message == WM_RBUTTONDBLCLK)) {
+              message_id == WM_RBUTTONDBLCLK)) {
     LOG(WARNING) << "Double click event being treated as single-click. "
                  << "This may result in different event processing behavior. "
                  << "If you need a single click try moving the mouse between "
@@ -449,10 +456,14 @@ bool SendMouseMoveImpl(long screen_x, long screen_y, base::OnceClosure task) {
     return true;
   }
 
-  // Form the input data containing the normalized absolute coordinates.
+  // Form the input data containing the normalized absolute coordinates. As of
+  // Windows 10 Fall Creators Update, moving to an absolute position of zero
+  // does not work. It seems that moving to 1,1 does, though.
   INPUT input = {INPUT_MOUSE};
-  input.mi.dx = static_cast<LONG>(std::ceil(screen_x * (65535.0 / max_x)));
-  input.mi.dy = static_cast<LONG>(std::ceil(screen_y * (65535.0 / max_y)));
+  input.mi.dx =
+      static_cast<LONG>(std::max(1.0, std::ceil(screen_x * (65535.0 / max_x))));
+  input.mi.dy =
+      static_cast<LONG>(std::max(1.0, std::ceil(screen_y * (65535.0 / max_y))));
   input.mi.dwFlags = MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_MOVE;
 
   scoped_refptr<InputDispatcher> dispatcher;