Introduce user customization of external HighDPI mode for 4K monitor.

ash/display/display_manager_unittest.cc

Index: ash/display/display_manager_unittest.cc
diff --git a/ash/display/display_manager_unittest.cc b/ash/display/display_manager_unittest.cc
index 55ccd03a6c856ea2364c4d1c5fba4cc4e62d90d6..2d3fc3e185920c9ce9196ec2f3398dbc1d5b649f 100644
--- a/ash/display/display_manager_unittest.cc
+++ b/ash/display/display_manager_unittest.cc
@@ -736,13 +736,19 @@ TEST_F(DisplayManagerTest, DontRememberBestResolution) {
   display_manager()->OnNativeDisplaysChanged(display_info_list);
 
   DisplayMode mode;
+  DisplayMode expected_mode;
+  expected_mode.size = gfx::Size(1000, 500);
   EXPECT_FALSE(
       display_manager()->GetSelectedModeForDisplayId(display_id, &mode));
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
 
   // Unsupported resolution.
   display_manager()->SetDisplayResolution(display_id, gfx::Size(800, 4000));
   EXPECT_FALSE(
       display_manager()->GetSelectedModeForDisplayId(display_id, &mode));
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
 
   // Supported resolution.
   display_manager()->SetDisplayResolution(display_id, gfx::Size(800, 300));
@@ -751,6 +757,9 @@ TEST_F(DisplayManagerTest, DontRememberBestResolution) {
   EXPECT_EQ("800x300", mode.size.ToString());
   EXPECT_EQ(59.0f, mode.refresh_rate);
   EXPECT_FALSE(mode.native);
+  expected_mode.size = gfx::Size(800, 300);
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
 
   // Best resolution.
   display_manager()->SetDisplayResolution(display_id, gfx::Size(1000, 500));
@@ -759,6 +768,9 @@ TEST_F(DisplayManagerTest, DontRememberBestResolution) {
   EXPECT_EQ("1000x500", mode.size.ToString());
   EXPECT_EQ(58.0f, mode.refresh_rate);
   EXPECT_TRUE(mode.native);
+  expected_mode.size = gfx::Size(1000, 500);
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
 }
 
 TEST_F(DisplayManagerTest, ResolutionFallback) {
@@ -965,6 +977,88 @@ TEST_F(DisplayManagerTest, UIScale) {
   EXPECT_EQ("1280x850", display.bounds().size().ToString());
 }
 
+TEST_F(DisplayManagerTest, UIScaleWithDisplayMode) {
+  int display_id = 1000;
+
+  // Setup the display modes with UI-scale.
+  DisplayInfo native_display_info =
+      CreateDisplayInfo(display_id, gfx::Rect(0, 0, 1280, 800));
+  std::vector<DisplayMode> display_modes;
+  const DisplayMode base_mode(gfx::Size(1280, 800), 60.0f, false, false);
+  std::vector<float> scales =
+      DisplayManager::GetScalesForDisplay(native_display_info);
+  for (size_t i = 0; i < scales.size(); i++) {
+    DisplayMode mode = base_mode;
+    mode.ui_scale = scales[i];
+    mode.native = (scales[i] == 1.0f);
+    display_modes.push_back(mode);
+  }
+  native_display_info.set_display_modes(display_modes);
+  std::vector<DisplayInfo> display_info_list;
+  display_info_list.push_back(native_display_info);
+  display_manager()->OnNativeDisplaysChanged(display_info_list);
+
+  DisplayMode expected_mode = base_mode;
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+
+  display_manager()->SetDisplayUIScale(display_id, 1.125f);
+  EXPECT_EQ(1.0, GetDisplayInfoAt(0).configured_ui_scale());
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+  display_manager()->SetDisplayUIScale(display_id, 0.8f);
+  EXPECT_EQ(1.0f, GetDisplayInfoAt(0).configured_ui_scale());
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+  display_manager()->SetDisplayUIScale(display_id, 0.75f);
+  EXPECT_EQ(1.0f, GetDisplayInfoAt(0).configured_ui_scale());
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+  display_manager()->SetDisplayUIScale(display_id, 0.625f);
+  EXPECT_EQ(1.0f, GetDisplayInfoAt(0).configured_ui_scale());
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+
+  gfx::Display::SetInternalDisplayId(display_id);
+
+  display_manager()->SetDisplayUIScale(display_id, 1.5f);
+  EXPECT_EQ(1.0f, GetDisplayInfoAt(0).configured_ui_scale());
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+  display_manager()->SetDisplayUIScale(display_id, 1.25f);
+  EXPECT_EQ(1.0f, GetDisplayInfoAt(0).configured_ui_scale());
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+  display_manager()->SetDisplayUIScale(display_id, 1.125f);
+  EXPECT_EQ(1.125f, GetDisplayInfoAt(0).configured_ui_scale());
+  expected_mode.ui_scale = 1.125f;
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+  display_manager()->SetDisplayUIScale(display_id, 0.8f);
+  EXPECT_EQ(0.8f, GetDisplayInfoAt(0).configured_ui_scale());
+  expected_mode.ui_scale = 0.8f;
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+  display_manager()->SetDisplayUIScale(display_id, 0.75f);
+  EXPECT_EQ(0.8f, GetDisplayInfoAt(0).configured_ui_scale());
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+  display_manager()->SetDisplayUIScale(display_id, 0.625f);
+  EXPECT_EQ(0.625f, GetDisplayInfoAt(0).configured_ui_scale());
+  expected_mode.ui_scale = 0.625f;
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+  display_manager()->SetDisplayUIScale(display_id, 0.6f);
+  EXPECT_EQ(0.625f, GetDisplayInfoAt(0).configured_ui_scale());
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+  display_manager()->SetDisplayUIScale(display_id, 0.5f);
+  EXPECT_EQ(0.5f, GetDisplayInfoAt(0).configured_ui_scale());
+  expected_mode.ui_scale = 0.5f;
+  EXPECT_TRUE(expected_mode.IsEquivalent(
+      display_manager()->GetActiveModeForDisplayId(display_id)));
+}
+
 TEST_F(DisplayManagerTest, UIScaleUpgradeToHighDPI) {
   int64 display_id = Shell::GetScreen()->GetPrimaryDisplay().id();
   gfx::Display::SetInternalDisplayId(display_id);