Allow using repeating decimal scale factor in command line.

Use these scale factor when 2.25, 1.77 and 2.66 are given from command line.

Bug: None

Change-Id: I20f227a80ed38eb3643a63abb50ba6c454036b41
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2448651Reviewed-by: Malay Keshav <malaykeshav@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#816516}

components/exo/wayland/zcr_remote_shell_unittest.cc

@@ -7,6 +7,7 @@
 #include "components/exo/test/exo_test_base.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
+#include "ui/display/types/display_constants.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/views/widget/widget.h"
 
@@ -19,11 +20,11 @@ TEST_F(ZcrRemoteShellTest, GetWorkAreaInsetsInPixel) {
 
   auto display = display::Screen::GetScreen()->GetPrimaryDisplay();
   const float device_scale_factor = display.device_scale_factor();
-  EXPECT_EQ(2.25f, device_scale_factor);
+  EXPECT_EQ(display::kDsf_2_252, device_scale_factor);
   gfx::Insets insets = wayland::GetWorkAreaInsetsInPixel(
       display, device_scale_factor, display.GetSizeInPixel(),
       display.work_area());
-  EXPECT_EQ(gfx::Insets(0, 0, 110, 0).ToString(), insets.ToString());
+  EXPECT_EQ(gfx::Insets(0, 0, 108, 0).ToString(), insets.ToString());
 
   auto secondary_display = GetSecondaryDisplay();
   gfx::Size secondary_size(secondary_display.size());
@@ -42,7 +43,7 @@ TEST_F(ZcrRemoteShellTest, GetWorkAreaInsetsInPixel) {
   gfx::Insets stable_insets = wayland::GetWorkAreaInsetsInPixel(
       display, device_scale_factor, display.GetSizeInPixel(),
       wayland::GetStableWorkArea(display));
-  EXPECT_EQ(gfx::Insets(0, 0, 110, 0).ToString(), stable_insets.ToString());
+  EXPECT_EQ(gfx::Insets(0, 0, 108, 0).ToString(), stable_insets.ToString());
   gfx::Insets secondary_stable_insets = wayland::GetWorkAreaInsetsInPixel(
       secondary_display, device_scale_factor, secondary_size_in_pixel,
       wayland::GetStableWorkArea(secondary_display));

ui/display/manager/managed_display_info.cc

@@ -54,6 +54,17 @@ bool GetDisplayBounds(const std::string& spec,
       sscanf(spec.c_str(), "%d+%d-%dx%d*%f", &x, &y, &width, &height,
              device_scale_factor) >= 4) {
     bounds->SetRect(x, y, width, height);
+
+    auto equals_within_epsilon = [device_scale_factor](float dsf) {
+      return std::abs(*device_scale_factor - dsf) < 0.01f;
+    };
+    if (equals_within_epsilon(1.77f)) {
+      *device_scale_factor = kDsf_1_777;
+    } else if (equals_within_epsilon(2.25f)) {
+      *device_scale_factor = kDsf_2_252;
+    } else if (equals_within_epsilon(2.66)) {
+      *device_scale_factor = kDsf_2_666;
+    }
     return true;
   }
   return false;