Add 2.25dsf support

BUG=b/74845106
TEST=covered by unittests

Change-Id: I1dde9c2ab19d08945f7ad4d9d2038dc1d0ff3e54
Reviewed-on: https://chromium-review.googlesource.com/1093518Reviewed-by: Malay Keshav <malaykeshav@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567180}

ui/display/manager/display_change_observer.cc

@@ -40,6 +40,7 @@ struct DeviceScaleFactorDPIThreshold {
 };
 
 const DeviceScaleFactorDPIThreshold kThresholdTableForInternal[] = {
+    {270.0f, 2.25f},
     {220.0f, 2.0f},
     {180.0f, 1.6f},
     {150.0f, 1.25f},

ui/display/manager/display_change_observer_unittest.cc

@@ -364,10 +364,13 @@ TEST_F(DisplayChangeObserverTest, FindDeviceScaleFactor) {
   // 12.3" 2400x1600
   EXPECT_EQ(2.0f, ComputeDeviceScaleFactor(12.3f, gfx::Rect(2400, 1600)));
 
+// 12.3" 3000x2000 (meowth)
+  EXPECT_EQ(2.25f, ComputeDeviceScaleFactor(12.3f, gfx::Rect(3000, 2000)));
+
   // Erroneous values should still work.
   EXPECT_EQ(1.0f, DisplayChangeObserver::FindDeviceScaleFactor(-100.0f));
   EXPECT_EQ(1.0f, DisplayChangeObserver::FindDeviceScaleFactor(0.0f));
-  EXPECT_EQ(2.0f, DisplayChangeObserver::FindDeviceScaleFactor(10000.0f));
+  EXPECT_EQ(2.25f, DisplayChangeObserver::FindDeviceScaleFactor(10000.0f));
 }
 
 TEST_F(DisplayChangeObserverTest,