[google_apis] Remove SPDY proxy key support

The code that used it was removed early this year. See the bug.

Bug: 1285486, 1377536
Change-Id: Iba6747024b891f1fe0659f353a32c1090af35f48
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3984602
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Auto-Submit: David Dorwin <ddorwin@chromium.org>
Commit-Queue: Mihai Sardarescu <msarda@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1064782}

google_apis/google_api_keys.cc

@@ -240,14 +240,6 @@ class APIKeyCache {
   }
 #endif
 
-  std::string GetSpdyProxyAuthValue() {
-#if defined(SPDY_PROXY_AUTH_VALUE)
-    return SPDY_PROXY_AUTH_VALUE;
-#else
-    return std::string();
-#endif
-  }
-
  private:
   // Gets a value for a key.  In priority order, this will be the value
   // provided via:
@@ -411,10 +403,6 @@ void SetOAuth2ClientSecret(OAuth2Client client,
 }
 #endif
 
-std::string GetSpdyProxyAuthValue() {
-  return g_api_key_cache.Get().GetSpdyProxyAuthValue();
-}
-
 bool IsGoogleChromeAPIKeyUsed() {
 #if defined(USE_OFFICIAL_GOOGLE_API_KEYS)
   return true;

google_apis/google_api_keys.h

@@ -136,8 +136,6 @@ void SetOAuth2ClientID(OAuth2Client client, const std::string& client_id);
 void SetOAuth2ClientSecret(OAuth2Client client,
                            const std::string& client_secret);
 #endif
-// Returns the auth token for the data reduction proxy.
-std::string GetSpdyProxyAuthValue();
 
 // Returns if the API key using in the current build is the one for official
 // Google Chrome.