Adds a Feature to disable promo browser commands

The added Feature is enabled by default and is meant to allow disabling
promo browser commands via Finch.

For more information see go/promos-deeplinking-settings

Bug: 1106421
Change-Id: Ia74973644657af5e8642021f78fd3f0a6c88dfc2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2335403Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Moe Ahmadi <mahmadi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794304}

chrome/browser/browser_features.cc

@@ -11,6 +11,10 @@ namespace features {
 const base::Feature kClosedTabCache{"ClosedTabCache",
                                     base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Enables executing the browser commands sent by the NTP promos.
+const base::Feature kEnablePromoBrowserCommands{
+    "EnablePromoBrowserCommands", base::FEATURE_ENABLED_BY_DEFAULT};
+
 #if defined(OS_CHROMEOS)
 // Enables being able to zoom a web page by double tapping in Chrome OS tablet
 // mode.

chrome/browser/browser_features.h

@@ -18,6 +18,8 @@ namespace features {
 
 extern const base::Feature kClosedTabCache;
 
+extern const base::Feature kEnablePromoBrowserCommands;
+
 #if defined(OS_CHROMEOS)
 extern const base::Feature kDoubleTapToZoomInTabletMode;
 #endif

chrome/browser/ui/webui/new_tab_page/promo_browser_command/promo_browser_command_handler.cc

@@ -4,7 +4,9 @@
 
 #include "chrome/browser/ui/webui/new_tab_page/promo_browser_command/promo_browser_command_handler.h"
 
+#include "base/feature_list.h"
 #include "base/metrics/histogram_functions.h"
+#include "chrome/browser/browser_features.h"
 #include "chrome/browser/command_updater_impl.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search/promos/promo_service.h"
@@ -25,6 +27,9 @@ PromoBrowserCommandHandler::PromoBrowserCommandHandler(
     : profile_(profile),
       command_updater_(std::make_unique<CommandUpdaterImpl>(this)),
       page_handler_(this, std::move(pending_page_handler)) {
+  if (!base::FeatureList::IsEnabled(features::kEnablePromoBrowserCommands))
+    return;
+
   // Explicitly enable supported commands.
   command_updater_->UpdateCommandEnabled(
       static_cast<int>(Command::kUnknownCommand), true);

chrome/browser/ui/webui/new_tab_page/promo_browser_command/promo_browser_command_handler_unittest.cc

@@ -7,6 +7,8 @@
 #include "base/bind.h"
 #include "base/run_loop.h"
 #include "base/test/metrics/histogram_tester.h"
+#include "base/test/scoped_feature_list.h"
+#include "chrome/browser/browser_features.h"
 #include "chrome/browser/command_updater_impl.h"
 #include "chrome/browser/promo_browser_command/promo_browser_command.mojom.h"
 #include "chrome/browser/ui/webui/new_tab_page/promo_browser_command/promo_browser_command_handler.h"
@@ -115,3 +117,21 @@ TEST_F(PromoBrowserCommandHandlerTest, SupportedCommands) {
   histogram_tester.ExpectBucketCount(
       PromoBrowserCommandHandler::kPromoBrowserCommandHistogramName, 0, 1);
 }
+
+TEST_F(PromoBrowserCommandHandlerTest, DisableHandlingCommands) {
+  base::HistogramTester histogram_tester;
+
+  // Disabling features::kEnablePromoBrowserCommands prevents the commands from
+  // being executed.
+  base::test::ScopedFeatureList feature_list;
+  feature_list.InitAndDisableFeature(features::kEnablePromoBrowserCommands);
+
+  // The PromoBrowserCommandHandler instance needs to be recreated for the
+  // feature to take effect.
+  command_handler_ = std::make_unique<PromoBrowserCommandHandler>(
+      mojo::PendingReceiver<CommandHandler>(), &profile_);
+
+  EXPECT_FALSE(ExecuteCommand(Command::kUnknownCommand, ClickInfo::New()));
+  histogram_tester.ExpectTotalCount(
+      PromoBrowserCommandHandler::kPromoBrowserCommandHistogramName, 0);
+}