Second attempt at fixing pointer lock issues with Windows HiDPI.

content/browser/renderer_host/input/web_input_event_builders_win.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/input/web_input_event_builders_win.h"
 
 #include "base/logging.h"
 #include "content/browser/renderer_host/input/web_input_event_util.h"
 #include "ui/gfx/win/dpi.h"
 
@@ skipping 170 matching lines @@
   POINT pos = {-1, -1};
   GetCursorPos(&pos);
   ScreenToClient(hwnd, &pos);
   return MAKELPARAM(pos.x, pos.y);
 }
 
 WebMouseEvent WebMouseEventBuilder::Build(HWND hwnd,
                                           UINT message,
                                           WPARAM wparam,
                                           LPARAM lparam,
                                           DWORD time_ms) {

[scottmg, 2015/03/09 21:33:18]

I doesn't seem particularly clear whether this should be dips or pixels. Would
it be possible to add a test maybe near
https://code.google.com/p/chromium/codesearch#chromium/src/content/renderer/i...
somewhere?

[ananta, 2015/03/09 22:55:59]

Added a content_unittest WebInputEventBuilderTest.TestMouseEventScale

   WebMouseEvent result;
 
   switch (message) {
   case WM_MOUSEMOVE:
     result.type = WebInputEvent::MouseMove;
     if (wparam & MK_LBUTTON)
       result.button = WebMouseEvent::ButtonLeft;
     else if (wparam & MK_MBUTTON)
       result.button = WebMouseEvent::ButtonMiddle;
     else if (wparam & MK_RBUTTON)
@@ skipping 42 matching lines @@
   DCHECK(time_ms);
   result.timeStampSeconds = time_ms / 1000.0;
 
   // set position fields:
 
   result.x = static_cast<short>(LOWORD(lparam));
   result.y = static_cast<short>(HIWORD(lparam));
   result.windowX = result.x;
   result.windowY = result.y;
 
-  // The mouse coordinates received here are device independent (DIPs). We need
-  // to convert them to physical coordinates before calling Windows APIs like
-  // ClientToScreen, etc.
-  gfx::Point scaled_screen_point(result.x, result.y);
-  scaled_screen_point = gfx::win::DIPToScreenPoint(scaled_screen_point);
-
-  POINT global_point = { scaled_screen_point.x(), scaled_screen_point.y() };
+  POINT global_point = { result.x, result.y };
   ClientToScreen(hwnd, &global_point);
 
-  scaled_screen_point.set_x(global_point.x);
-  scaled_screen_point.set_y(global_point.y);
+  // We need to convert the global point back to DIP before using it.
+  gfx::Point dip_global_point = gfx::win::ScreenToDIPPoint(
+      gfx::Point(global_point.x, global_point.y));
 
-  // We need to convert the point back to DIP before using it.
-  gfx::Point dip_screen_point = gfx::win::ScreenToDIPPoint(
-      scaled_screen_point);
-
-  result.globalX = dip_screen_point.x();
-  result.globalY = dip_screen_point.y();
+  result.globalX = dip_global_point.x();
+  result.globalY = dip_global_point.y();
 
   // calculate number of clicks:
 
   // This differs slightly from the WebKit code in WebKit/win/WebView.cpp
   // where their original code looks buggy.
   static int last_click_position_x;
   static int last_click_position_y;
   static WebMouseEvent::Button last_click_button = WebMouseEvent::ButtonLeft;
 
   double current_time = result.timeStampSeconds;
@@ skipping 186 matching lines @@
     result.wheelTicksX = wheel_delta;
   } else {
     result.deltaY = scroll_delta;
     result.wheelTicksY = wheel_delta;
   }
 
   return result;
 }
 
 }  // namespace content