Added flag in chrome://flags to enable the New Launcher UI.

chrome/browser/flag_descriptions.cc

Index: chrome/browser/flag_descriptions.cc
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index 27a963351a282e3426826dd9d3f41ea2e2e118bd..6ea4a978213ab7d6fe803a5bde794efd33dd89cb 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -2927,6 +2927,12 @@ const char kDisplayColorCalibrationDescription[] =
     "Allow color calibration of the display if the display supports the "
     "feature.";
 
+const char kEnableNewAppListUIName[] = "Enable The Peeking Launcher";

[stevenjb, 2017/06/30 21:17:25]

Maybe enable-peeking-app-list?

[newcomer, 2017/06/30 21:40:24]

My PM wants the flag to say Launcher instead of app list, and msw@ has asked me
to keep "Launcher" out of the code base to the max extent. This is why it is
called Launcher here and app list elsewhere.

+
+const char kEnableNewAppListUIDescription[] =
+    "The new launcher UI supports touch and provides more space for upcoming "
+    "features.";
+
 const char kMemoryPressureThresholdName[] =
     "Memory discard strategy for advanced pressure handling";