Add a new chrome flag for Ambient Mode.

This CL adds a new flag in chrome://flags to enable/disable the Ambient
Mode feature.

Bug: b/149244227
Test: manually.
Change-Id: I7f07020db81fc61962bbe923c62ce1837634d94c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2053037
Commit-Queue: Meilin Wang <meilinw@chromium.org>
Reviewed-by: Tao Wu <wutao@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#742284}

chrome/browser/about_flags.cc

@@ -4975,6 +4975,12 @@ const FeatureEntry kFeatureEntries[] = {
      flag_descriptions::kExportTaggedPDFDescription, kOsDesktop,
      FEATURE_VALUE_TYPE(features::kExportTaggedPDF)},
 
+#if defined(OS_CHROMEOS)
+    {"enable-ambient-mode", flag_descriptions::kEnableAmbientModeName,
+     flag_descriptions::kEnableAmbientModeDescription, kOsCrOS,
+     FEATURE_VALUE_TYPE(chromeos::features::kAmbientModeFeature)},
+#endif  // defined(OS_CHROMEOS)
+
     // NOTE: Adding a new flag requires adding a corresponding entry to enum
     // "LoginCustomFlags" in tools/metrics/histograms/enums.xml. See "Flag
     // Histograms" in tools/metrics/histograms/README.md (run the

chrome/browser/flag-metadata.json

@@ -921,6 +921,11 @@
     "owners": ["rhalavati", "chrome-privacy-core@google.com"],
     "expiry_milestone": 87
   },
+  {
+    "name": "enable-ambient-mode",
+    "owners": [ "croissant-eng" ],
+    "expiry_milestone": 88
+  },
   {
     "name": "enable-android-autofill-accessibility",
     "owners": [ "ftirelo" ],
@@ -986,11 +991,6 @@
     "owners": [ "croissant-eng" ],
     "expiry_milestone": 88
   },
-  {
-    "name": "enable-assistant-key-remapping",
-    "owners": [ "croissant-eng" ],
-    "expiry_milestone": 78
-  },
   {
     "name": "enable-assistant-launcher-integration",
     "owners": [ "croissant-eng" ],

chrome/browser/flag_descriptions.cc

@@ -3259,6 +3259,10 @@ const char kEnableArcUnifiedAudioFocusDescription[] =
     "If audio focus is enabled in Chrome then this will delegate audio focus "
     "control in Android apps to Chrome.";
 
+extern const char kEnableAmbientModeName[] = "Enable Ambient Mode";
+extern const char kEnableAmbientModeDescription[] =
+    "Enable Ambient Mode to show an enhanced lock screen with more functions";
+
 const char kEnableAssistantAppSupportName[] = "Enable Assistant App Support";
 const char kEnableAssistantAppSupportDescription[] =
     "Enable the Assistant App Support feature";

chrome/browser/flag_descriptions.h

@@ -1888,6 +1888,9 @@ extern const char kEnableAppReinstallZeroStateDescription[];
 extern const char kEnableArcUnifiedAudioFocusName[];
 extern const char kEnableArcUnifiedAudioFocusDescription[];
 
+extern const char kEnableAmbientModeName[];
+extern const char kEnableAmbientModeDescription[];
+
 extern const char kEnableAssistantAppSupportName[];
 extern const char kEnableAssistantAppSupportDescription[];
 

tools/metrics/histograms/enums.xml

@@ -39309,6 +39309,7 @@ from previous Chrome versions.
   <int value="775075949" label="ImeInputLogicHmm:enabled"/>
   <int value="777667507" label="DesktopPWAsLinkCapturing:enabled"/>
   <int value="779086132" label="enable-data-reduction-proxy-alt"/>
+  <int value="779703052" label="ChromeOSAmbientMode:enabled"/>
   <int value="779849093" label="OfflinePagesCTSuppressNotifications:disabled"/>
   <int value="782167080" label="enable-new-qp-input-view"/>
   <int value="783270752" label="AndroidHistoryManager:enabled"/>
@@ -39985,6 +39986,7 @@ from previous Chrome versions.
   <int value="1622131033" label="ozone-test-single-overlay-support"/>
   <int value="1622672308" label="ReaderMode:enabled"/>
   <int value="1626824478" label="ExperimentalAppBanners:disabled"/>
+  <int value="1627666567" label="ChromeOSAmbientMode:disabled"/>
   <int value="1628259213" label="DuetTabStripIntegrationAndroid:enabled"/>
   <int value="1628831121" label="SafeBrowsingUseLocalBlacklistsV2:enabled"/>
   <int value="1630159957" label="SharingSendViaSync:disabled"/>