Set dpi_ correctly during main window creation

For some Chrome windows the dpi_ setting cannot be set during window
creation because the window location is not yet known. For other windows
the dpi_ setting _must_ be set during window creation. This change
handles both cases by setting dpi_ if the window size/location is being
specified. This then handles both the task manager and main window
cases.

Bug: 1282804
Change-Id: Ic85dfb1646e9d063af324cc79736b660cea1acdc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3378579
Reviewed-by: Robert Liao <robliao@chromium.org>
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>
Cr-Commit-Position: refs/heads/main@{#957715}

ui/views/win/hwnd_message_handler.cc

@@ -439,6 +439,7 @@ void HWNDMessageHandler::Init(HWND parent, const gfx::Rect& bounds) {
   GetMonitorAndRects(bounds.ToRECT(), &last_monitor_, &last_monitor_rect_,
                      &last_work_area_);
 
+  initial_bounds_valid_ = !bounds.IsEmpty();
   // Create the window.
   WindowImpl::Init(parent, bounds);
 
@@ -1646,6 +1647,12 @@ LRESULT HWNDMessageHandler::OnCreate(CREATESTRUCT* create_struct) {
       std::make_unique<ui::SessionChangeObserver>(base::BindRepeating(
           &HWNDMessageHandler::OnSessionChange, base::Unretained(this)));
 
+  // If the window was initialized with a specific size/location then we know
+  // the DPI and thus must initialize dpi_ now. See https://crbug.com/1282804
+  // for details.
+  if (initial_bounds_valid_)
+    dpi_ = display::win::ScreenWin::GetDPIForHWND(hwnd());
+
   // TODO(beng): move more of NWW::OnCreate here.
   return 0;
 }

ui/views/win/hwnd_message_handler.h

@@ -643,6 +643,10 @@ class VIEWS_EXPORT HWNDMessageHandler : public gfx::WindowImpl,
   // The current DPI.
   int dpi_;
 
+  // This is true if the window is created with a specific size/location, as
+  // opposed to having them set after window creation.
+  bool initial_bounds_valid_ = false;
+
   // Whether EnableNonClientDpiScaling was called successfully with this window.
   // This flag exists because EnableNonClientDpiScaling must be called during
   // WM_NCCREATE and EnableChildWindowDpiMessage is called after window