Add 2.5x scale factor support

Bug: b/139810037
Test: covered by unittest. also tested manually.

Change-Id: I18a1f7e3d368d51823a3cd1b21e5d905fcc3d00e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1757686Reviewed-by: Yusuke Sato <yusukes@chromium.org>
Reviewed-by: Jun Mukai <mukai@chromium.org>
Commit-Queue: Mitsuru Oshima (slow) <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#689570}

components/arc/arc_util.cc

@@ -275,13 +275,15 @@ bool IsArcPlayAutoInstallDisabled() {
 
 // static
 int32_t GetLcdDensityForDeviceScaleFactor(float device_scale_factor) {
-  // Keep this consistent with wayland_client.cpp on Android side.
-  // TODO(oshima): Consider sending this through wayland.
+  // TODO(b/131884992): Remove the logic to update default lcd density once
+  // per-display-density is supported.
   constexpr float kEpsilon = 0.001;
   if (std::abs(device_scale_factor - 2.25f) < kEpsilon)
     return 280;
   if (std::abs(device_scale_factor - 1.6f) < kEpsilon)
     return 213;  // TVDPI
+  if (std::abs(device_scale_factor - 2.5f) < kEpsilon)
+    return 320;  // XHDPI
 
   constexpr float kChromeScaleToAndroidScaleRatio = 0.75f;
   constexpr int32_t kDefaultDensityDpi = 160;

components/arc/arc_util_unittest.cc

@@ -266,6 +266,7 @@ TEST_F(ArcUtilTest, ScaleFactorToDensity) {
   EXPECT_EQ(213, GetLcdDensityForDeviceScaleFactor(1.6f));
   EXPECT_EQ(240, GetLcdDensityForDeviceScaleFactor(2.0f));
   EXPECT_EQ(280, GetLcdDensityForDeviceScaleFactor(2.25f));
+  EXPECT_EQ(320, GetLcdDensityForDeviceScaleFactor(2.5f));
 
   // Bad scale factors shouldn't blow up.
   EXPECT_EQ(160, GetLcdDensityForDeviceScaleFactor(0.5f));

ui/display/manager/display_change_observer.cc

@@ -45,8 +45,8 @@ struct DeviceScaleFactorDPIThreshold {
 // Update the list of zoom levels whenever a new device scale factor is added
 // here. See zoom level list in /ui/display/manager/display_util.cc
 const DeviceScaleFactorDPIThreshold kThresholdTableForInternal[] = {
-    {270.0f, 2.25f}, {220.0f, 2.0f}, {180.0f, 1.6f},
-    {150.0f, 1.25f}, {0.0f, 1.0f},
+    {320.f, 2.5f},  {270.0f, 2.25f}, {220.0f, 2.0f},
+    {180.0f, 1.6f}, {150.0f, 1.25f}, {0.0f, 1.0f},
 };
 
 // Returns a list of display modes for the given |output| that doesn't exclude

ui/display/manager/display_change_observer_unittest.cc

@@ -207,13 +207,16 @@ TEST_P(DisplayChangeObserverTest, FindDeviceScaleFactor) {
   // 12.3" 2400x1600
   EXPECT_EQ(2.0f, ComputeDeviceScaleFactor(12.3f, gfx::Rect(2400, 1600)));
 
-// 12.3" 3000x2000 (meowth)
+  // 12.3" 3000x2000
   EXPECT_EQ(2.25f, ComputeDeviceScaleFactor(12.3f, gfx::Rect(3000, 2000)));
 
+  // 13.1" 3840x2160
+  EXPECT_EQ(2.5f, ComputeDeviceScaleFactor(13.1f, gfx::Rect(3840, 2160)));
+
   // Erroneous values should still work.
   EXPECT_EQ(1.0f, DisplayChangeObserver::FindDeviceScaleFactor(-100.0f));
   EXPECT_EQ(1.0f, DisplayChangeObserver::FindDeviceScaleFactor(0.0f));
-  EXPECT_EQ(2.25f, DisplayChangeObserver::FindDeviceScaleFactor(10000.0f));
+  EXPECT_EQ(2.5f, DisplayChangeObserver::FindDeviceScaleFactor(10000.0f));
 }
 
 TEST_P(DisplayChangeObserverTest,

ui/display/manager/display_util.cc

@@ -49,11 +49,12 @@ constexpr std::array<ZoomListBucket, 8> kZoomListBuckets{{
 // zoom values that includes a zoom level to go to the native resolution of the
 // display. Ensure that the list of DSFs are in sync with the list of default
 // device scale factors in display_change_observer.cc.
-constexpr std::array<ZoomListBucketDsf, 4> kZoomListBucketsForDsf{{
+constexpr std::array<ZoomListBucketDsf, 5> kZoomListBucketsForDsf{{
     {1.25f, {0.7f, 1.f / 1.25f, 0.85f, 0.9f, 0.95f, 1.f, 1.1f, 1.2f, 1.3f}},
     {1.6f, {1.f / 1.6f, 0.7f, 0.75f, 0.8f, 0.85f, 0.9f, 1.f, 1.15f, 1.3f}},
     {2.f, {1.f / 2.f, 0.6f, 0.7f, 0.8f, 0.9f, 1.f, 1.1f, 1.25f, 1.5f}},
     {2.25f, {1.f / 2.25f, 0.6f, 0.7f, 0.8f, 0.9f, 1.f, 1.15f, 1.3f, 1.5f}},
+    {2.5f, {1.f / 2.5f, 0.5f, 0.6f, 0.8f, 0.9f, 1.f, 1.2f, 1.35f, 1.5f}},
 }};
 
 bool WithinEpsilon(float a, float b) {

ui/display/manager/display_utils_unittest.cc

@@ -46,7 +46,7 @@ TEST_F(DisplayUtilTest, DisplayZooms) {
 }
 
 TEST_F(DisplayUtilTest, DisplayZoomsWithInternalDsf) {
-  std::vector<float> kDsfs = {1.25f, 1.6f, 2.f, 2.25f};
+  std::vector<float> kDsfs = {1.25f, 1.6f, 2.f, 2.25f, 2.5f};
 
   for (const auto& dsf : kDsfs) {
     SCOPED_TRACE(base::StringPrintf("dsf=%f", dsf));