[Profile picker] Make the window fit well on the screen

This CL makes sure that the profile picker window fits on the current
screen. Moreover, it forces the window to be somewhat smaller then the
current screen so that it still looks like a dialog window.

Bug: 773501
Change-Id: If5fef1920387c6fd421c3b7257426e6bacd6fdad
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2362887
Commit-Queue: Jan Krcal <jkrcal@chromium.org>
Commit-Queue: David Roger <droger@chromium.org>
Auto-Submit: Jan Krcal <jkrcal@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799091}

chrome/browser/ui/views/profiles/profile_picker_view.cc

@@ -32,6 +32,7 @@ namespace {
 ProfilePickerView* g_profile_picker_view = nullptr;
 constexpr int kWindowWidth = 1024;
 constexpr int kWindowHeight = 758;
+constexpr float kMaxRatioOfWorkArea = 0.9;
 }  // namespace
 
 // static
@@ -117,7 +118,14 @@ void ProfilePickerView::Init(Profile* system_profile) {
 }
 
 gfx::Size ProfilePickerView::CalculatePreferredSize() const {
-  return gfx::Size(kWindowWidth, kWindowHeight);
+  gfx::Size preferred_size = gfx::Size(kWindowWidth, kWindowHeight);
+  gfx::Size work_area_size = GetWidget()->GetWorkAreaBoundsInScreen().size();
+  // Keep the window smaller then |work_area_size| so that it feels more like a
+  // dialog then like the actual Chrome window.
+  gfx::Size max_dialog_size = ScaleToFlooredSize(
+      work_area_size, kMaxRatioOfWorkArea, kMaxRatioOfWorkArea);
+  preferred_size.SetToMin(max_dialog_size);
+  return preferred_size;
 }
 
 void ProfilePickerView::WindowClosing() {