Remove PO2TS::DiagnosticsClient

This infrastructure is no longer used after
https://chromium-review.googlesource.com/c/chromium/src/+/1228197.

Bug: 883722
Change-Id: I9871ce8297ab42a8b173e61880570e076ae9277c
Reviewed-on: https://chromium-review.googlesource.com/1235575
Commit-Queue: Colin Blundell <blundell@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593497}

components/signin/core/browser/profile_oauth2_token_service.cc

@@ -15,8 +15,7 @@ ProfileOAuth2TokenService::ProfileOAuth2TokenService(
     std::unique_ptr<OAuth2TokenServiceDelegate> delegate)
     : OAuth2TokenService(std::move(delegate)),
       user_prefs_(user_prefs),
-      all_credentials_loaded_(false),
-      diagnostics_client_(nullptr) {
+      all_credentials_loaded_(false) {
   DCHECK(user_prefs_);
   AddObserver(this);
 }
@@ -78,14 +77,6 @@ void ProfileOAuth2TokenService::OnRefreshTokenAvailable(
     is_valid = false;
   }
 
-  // NOTE: The code executed in the rest of this method does not affect the
-  // state of the accounts in this object, so it doesn't matter whether the
-  // callout to |diagnostics_client_| is made before or after. If that fact ever
-  // changes, it will be necessary to reason about what the ordering should be.
-  if (diagnostics_client_) {
-    diagnostics_client_->WillFireOnRefreshTokenAvailable(account_id, is_valid);
-  }
-
   CancelRequestsForAccount(account_id);
   ClearCacheForAccount(account_id);
 }
@@ -95,14 +86,6 @@ void ProfileOAuth2TokenService::OnRefreshTokenRevoked(
   // If this was the last token, recreate the device ID.
   RecreateDeviceIdIfNeeded();
 
-  // NOTE: The code executed in the rest of this method does not affect the
-  // state of the accounts in this object, so it doesn't matter whether the
-  // callout to |diagnostics_client_| is made before or after. If that fact ever
-  // changes, it will be necessary to reason about what the ordering should be.
-  if (diagnostics_client_) {
-    diagnostics_client_->WillFireOnRefreshTokenRevoked(account_id);
-  }
-
   CancelRequestsForAccount(account_id);
   ClearCacheForAccount(account_id);
 }

components/signin/core/browser/profile_oauth2_token_service.h

@@ -79,37 +79,10 @@ class ProfileOAuth2TokenService : public OAuth2TokenService,
  private:
   friend class identity::IdentityManager;
 
-  // Interface that gives information on internal TokenService operations. Only
-  // for use by IdentityManager during the conversion of the codebase to use
-  // //services/identity/public/cpp.
-  // NOTE: This interface is defined on ProfileOAuth2TokenService rather than
-  // on the OAuth2TokenService base class for multiple reasons:
-  // (1) The base class already has a DiagnosticsObserver interface, from
-  // which this interface differs because there can be only one instance.
-  // (2) PO2TS itself observes O2TS and for correctness must receive observer
-  // callbacks before any other O2TS observer. Hence, these DiagnosticsClient
-  // callouts must go *inside* PO2TS's implementations of the O2TS observer
-  // methods.
-  class DiagnosticsClient {
-   public:
-    // Sent just before OnRefreshTokenAvailable() is fired on observers.
-    // |is_valid| indicates whether the token is valid.
-    virtual void WillFireOnRefreshTokenAvailable(const std::string& account_id,
-                                                 bool is_valid) = 0;
-    // Sent just before OnRefreshTokenRevoked() is fired on observers.
-    virtual void WillFireOnRefreshTokenRevoked(
-        const std::string& account_id) = 0;
-  };
-
   void OnRefreshTokenAvailable(const std::string& account_id) override;
   void OnRefreshTokenRevoked(const std::string& account_id) override;
   void OnRefreshTokensLoaded() override;
 
-  void set_diagnostics_client(DiagnosticsClient* diagnostics_client) {
-    DCHECK(!diagnostics_client_ || !diagnostics_client);
-    diagnostics_client_ = diagnostics_client;
-  }
-
   // Creates a new device ID if there are no accounts, or if the current device
   // ID is empty.
   void RecreateDeviceIdIfNeeded();
@@ -119,9 +92,6 @@ class ProfileOAuth2TokenService : public OAuth2TokenService,
   // Whether all credentials have been loaded.
   bool all_credentials_loaded_;
 
-  // The DiagnosticsClient object associated with this object. May be null.
-  DiagnosticsClient* diagnostics_client_;
-
   DISALLOW_COPY_AND_ASSIGN(ProfileOAuth2TokenService);
 };