Split buckets on boot complete

Also clean up a bit of code on splitting on app upgrades

Piggy-backed off the app upgrade tests, adding parameterized tests to
also test boot complete event.

Refactored some value metric test code to increase code reuse and
assertions.

Fixed a broken value metric test that had assertions commented out.

Refactored NamedLatch into MultiConditionTrigger to avoid creating a
thread before necessary.

Test: atest statsd_test
Test: push a simple test config, reboot, wait, get data. Made sure
the bucket was split
Bug: 144099206
Bug: 154511974

Change-Id: I73858b5db08e8cda762bd8091b30da8738d1fd88
diff --git a/cmds/statsd/src/utils/MultiConditionTrigger.h b/cmds/statsd/src/utils/MultiConditionTrigger.h
new file mode 100644
index 0000000..51f6029
--- /dev/null
+++ b/cmds/statsd/src/utils/MultiConditionTrigger.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#pragma once
+
+#include <gtest/gtest_prod.h>
+
+#include <mutex>
+#include <set>
+
+namespace android {
+namespace os {
+namespace statsd {
+
+/**
+ * This class provides a utility to wait for a set of named conditions to occur.
+ *
+ * It will execute the trigger runnable in a detached thread once all conditions have been marked
+ * true.
+ */
+class MultiConditionTrigger {
+public:
+    explicit MultiConditionTrigger(const std::set<std::string>& conditionNames,
+                                   std::function<void()> trigger);
+
+    MultiConditionTrigger(const MultiConditionTrigger&) = delete;
+    MultiConditionTrigger& operator=(const MultiConditionTrigger&) = delete;
+
+    // Mark a specific condition as true. If this condition has called markComplete already or if
+    // the event was not specified in the constructor, the function is a no-op.
+    void markComplete(const std::string& eventName);
+
+private:
+    mutable std::mutex mMutex;
+    std::set<std::string> mRemainingConditionNames;
+    std::function<void()> mTrigger;
+    bool mCompleted;
+
+    FRIEND_TEST(MultiConditionTriggerTest, TestCountDownCalledBySameEventName);
+};
+}  // namespace statsd
+}  // namespace os
+}  // namespace android