[Extensions] Add logic for when to show the toolbar redesign bubble.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 61151eb1ef3ebcc5937aa2d18c2b105e5fd5e473..71195b0a6babd21048681514fc547fde47fb39fc 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1218,13 +1218,20 @@ const char kEasyUnlockShowTutorial[] = "easy_unlock.show_tutorial";
 // A cache of zero suggest results using JSON serialized into a string.
 const char kZeroSuggestCachedResults[] = "zerosuggest.cachedresults";
 
+#if defined(ENABLE_EXTENSIONS) && !defined(OS_ANDROID) && !defined(OS_IOS)
 // These device IDs are used by the copresence component, to uniquely identify
 // this device to the server. For privacy, authenticated and unauthenticated
 // calls are made using different device IDs.
-#if defined(ENABLE_EXTENSIONS) && !defined(OS_ANDROID) && !defined(OS_IOS)
 const char kCopresenceAuthenticatedDeviceId[] =
     "apps.copresence.auth_device_id";
 const char kCopresenceAnonymousDeviceId[] = "apps.copresence.unauth_device_id";
+
+// Used to indicate whether or not the toolbar redesign bubble has been shown
+// and acknowledged, and the last time the bubble was shown.
+const char kToolbarIconSurfacingBubbleAcknowledged[] =
+    "toolbar_icon_surfacing_bubble_acknowledged";
+extern const char kToolbarIconSurfacingBubbleLastShowTime[] =
+    "toolbar_icon_surfacing_bubble_show_time";
 #endif
 
 // Whether WebRTC should bind to individual NICs to explore all possible routing