Add chrome://flags entry for new-tab animation

Bug: None
Change-Id: I8eab3c0203df3997f846a4508644534492d82043
Reviewed-on: https://chromium-review.googlesource.com/c/1372550
Commit-Queue: Peter Boström <pbos@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615823}

chrome/browser/about_flags.cc

@@ -1516,6 +1516,11 @@ const FeatureEntry kFeatureEntries[] = {
     {"new-tab-button-position", flag_descriptions::kNewTabButtonPosition,
      flag_descriptions::kNewTabButtonPositionDescription, kOsDesktop,
      MULTI_VALUE_TYPE(kNewTabButtonPositionChoices)},
+#if !defined(OS_ANDROID)
+    {"new-tab-loading-animation", flag_descriptions::kNewTabLoadingAnimation,
+     flag_descriptions::kNewTabLoadingAnimationDescription, kOsDesktop,
+     FEATURE_VALUE_TYPE(features::kNewTabLoadingAnimation)},
+#endif  // !defined(OS_ANDROID)
     {"single-tab-mode", flag_descriptions::kSingleTabMode,
      flag_descriptions::kSingleTabModeDescription, kOsDesktop,
      FEATURE_VALUE_TYPE(features::kSingleTabMode)},

chrome/browser/flag-metadata.json

@@ -2510,6 +2510,11 @@
     // "owners": [ "your-team" ],
     "expiry_milestone": 76
   },
+  {
+    "name": "new-tab-loading-animation",
+    "owners": [ "pbos@chromium.org" ],
+    "expiry_milestone": 76
+  },
   {
     "name": "new-usb-backend",
     "owners": [ "reillyg@chromium.org" ],

chrome/browser/flag_descriptions.cc

@@ -1270,6 +1270,10 @@ const char kNewblueName[] = "Newblue";
 const char kNewblueDescription[] =
     "Enables the use of newblue Bluetooth daemon.";
 
+const char kNewTabLoadingAnimation[] = "New tab-loading animation";
+const char kNewTabLoadingAnimationDescription[] =
+    "Enables a new look for the tab-loading animation.";
+
 const char kNewTabButtonPosition[] = "New tab button position";
 const char kNewTabButtonPositionDescription[] =
     "Controls placement of the new tab button within the tabstrip.";

chrome/browser/flag_descriptions.h

@@ -774,6 +774,9 @@ extern const char kNewUsbBackendDescription[];
 extern const char kNewblueName[];
 extern const char kNewblueDescription[];
 
+extern const char kNewTabLoadingAnimation[];
+extern const char kNewTabLoadingAnimationDescription[];
+
 extern const char kNewTabButtonPosition[];
 extern const char kNewTabButtonPositionDescription[];
 extern const char kNewTabButtonPositionOppositeCaption[];

tools/metrics/histograms/enums.xml

@@ -29886,6 +29886,7 @@ from previous Chrome versions.
       label="AutofillLocalCardMigrationShowFeedback:disabled"/>
   <int value="-1278796760" label="QueryInOmnibox:enabled"/>
   <int value="-1276912933" label="enable-quick-unlock-pin"/>
+  <int value="-1272593346" label="NewTabLoadingAnimation:disabled"/>
   <int value="-1271563519" label="enable-appcontainer"/>
   <int value="-1269093329" label="AndroidOmniboxPreviewsBadge:disabled"/>
   <int value="-1269084216" label="ash-md"/>
@@ -30188,6 +30189,7 @@ from previous Chrome versions.
   <int value="-742469530" label="DriveFS:disabled"/>
   <int value="-741806604" label="DownloadsUi:disabled"/>
   <int value="-738957187" label="OmniboxUIExperimentSwapTitleAndUrl:disabled"/>
+  <int value="-735084806" label="NewTabLoadingAnimation:enabled"/>
   <int value="-727860269" label="WebAuthenticationBle:disabled"/>
   <int value="-726892130" label="AndroidMessagesIntegration:disabled"/>
   <int value="-723224470" label="enable-password-force-saving:enabled"/>