Fixing the super-long delay when GCMAccountTracker posts a task

* In order to sort out dependencies between initialization of components, I am doing work only when I have a valid GCM connection going (this means all the infrastructure is up and running).
* I am also making sure that time to next token reporting is always between 0 and 12 hours.

BUG=453018

Review URL: https://codereview.chromium.org/885753002

Cr-Commit-Position: refs/heads/master@{#313754}

chrome/browser/services/gcm/gcm_account_tracker.cc

@@ -80,6 +80,11 @@ void GCMAccountTracker::Start() {
 }
 
 void GCMAccountTracker::ScheduleReportTokens() {
+  // Shortcutting here, in case GCM Driver is not yet connected. In that case
+  // reporting will be scheduled/started when the connection is made.
+  if (!driver_->IsConnected())
+    return;
+
   DVLOG(1) << "Deferring the token reporting for: "
            << GetTimeToNextTokenReporting().InSeconds() << " seconds.";
 
@@ -164,8 +169,12 @@ void GCMAccountTracker::OnGetTokenFailure(
 }
 
 void GCMAccountTracker::OnConnected(const net::IPEndPoint& ip_endpoint) {
+  // We are sure here, that GCM is running and connected. We can start reporting
+  // tokens if reporting is due now, or schedule reporting for later.
   if (IsTokenReportingRequired())
     ReportTokens();
+  else
+    ScheduleReportTokens();
 }
 
 void GCMAccountTracker::OnDisconnected() {
@@ -276,8 +285,20 @@ base::TimeDelta GCMAccountTracker::GetTimeToNextTokenReporting() const {
       driver_->GetLastTokenFetchTime() +
       base::TimeDelta::FromMilliseconds(kTokenReportingIntervalMs) -
       base::Time::Now();
-  return time_till_next_reporting < base::TimeDelta() ?
-             base::TimeDelta() : time_till_next_reporting;
+
+  // Case when token fetching is overdue.
+  if (time_till_next_reporting < base::TimeDelta())
+    return base::TimeDelta();
+
+  // Case when calculated period is larger than expected, including the
+  // situation when the method is called before GCM driver is completely
+  // initialized.
+  if (time_till_next_reporting >
+          base::TimeDelta::FromMilliseconds(kTokenReportingIntervalMs)) {
+    return base::TimeDelta::FromMilliseconds(kTokenReportingIntervalMs);
+  }
+
+  return time_till_next_reporting;
 }
 
 void GCMAccountTracker::DeleteTokenRequest(

chrome/browser/services/gcm/gcm_account_tracker_unittest.cc

@@ -476,9 +476,22 @@ TEST_F(GCMAccountTrackerTest, GetTimeToNextTokenReporting) {
   // At this point the last token fetch time is never.
   EXPECT_EQ(base::TimeDelta(), GetTimeToNextTokenReporting());
 
+  // Regular case. The tokens have been just reported.
   driver()->SetLastTokenFetchTime(base::Time::Now());
   EXPECT_TRUE(GetTimeToNextTokenReporting() <=
                   base::TimeDelta::FromSeconds(12 * 60 * 60));
+
+  // A case when gcm driver is not yet initialized.
+  driver()->SetLastTokenFetchTime(base::Time::Max());
+  EXPECT_EQ(base::TimeDelta::FromSeconds(12 * 60 * 60),
+            GetTimeToNextTokenReporting());
+
+  // A case when token reporting calculation is expected to result in more than
+  // 12 hours, in which case we expect exactly 12 hours.
+  driver()->SetLastTokenFetchTime(base::Time::Now() +
+      base::TimeDelta::FromDays(2));
+  EXPECT_EQ(base::TimeDelta::FromSeconds(12 * 60 * 60),
+            GetTimeToNextTokenReporting());
 }
 
 // Tests conditions when token reporting is required.