Add unique OTR profile id creator.

Adds a OTRProfileID::CreateUnique to create a unique OffTheRecrord
profile id with the given prefix.

Bug: 1033903
Change-Id: Iaa6408a17d72521b8c22feec82843ad4081abece
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2145875Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Commit-Queue: Ramin Halavati <rhalavati@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758766}

chrome/browser/profiles/profile.cc

@@ -111,6 +111,16 @@ const Profile::OTRProfileID Profile::OTRProfileID::PrimaryID() {
   return OTRProfileID("profile::primary_otr");
 }
 
+// static
+int Profile::OTRProfileID::first_unused_index_ = 0;
+
+// static
+Profile::OTRProfileID Profile::OTRProfileID::CreateUnique(
+    const std::string& profile_id_prefix) {
+  return OTRProfileID(base::StringPrintf("%s-%i", profile_id_prefix.c_str(),
+                                         first_unused_index_++));
+}
+
 const std::string& Profile::OTRProfileID::ToString() const {
   return profile_id_;
 }

chrome/browser/profiles/profile.h

@@ -115,6 +115,9 @@ class Profile : public content::BrowserContext {
     // |GuestID| when the use cases are reduced.
     static const OTRProfileID PrimaryID();
 
+    // Creates a unique OTR profile id with the given profile id prefix.
+    static OTRProfileID CreateUnique(const std::string& profile_id_prefix);
+
     bool operator==(const OTRProfileID& other) const {
       return profile_id_ == other.profile_id_;
     }
@@ -137,6 +140,8 @@ class Profile : public content::BrowserContext {
     // message.
     const std::string& ToString() const;
 
+    static int first_unused_index_;
+
     const std::string profile_id_;
   };