Reroute surfaceflinger pulled atoms

Add a binder interface for pulling surfaceflinger atoms, and make
timestats return a vector of bytestring for the result of a pull,
instead of an AStatsEventList. This is part of a topic to reroute the
surfaceflinger pullers through system server to break surfaceflinger's
dependencies on libstatpull/libstatssocket. This will help enable
removing statsd from the bootstrap apexes.

Test: statsd_testrive 10062 10063
Test: updated the unit tests
Test: atest libsurfaceflinger_unittest
Bug: 184698814
Change-Id: I417b43dd6974d5f00cdb37215cccebf176525932
diff --git a/services/surfaceflinger/TimeStats/TimeStats.h b/services/surfaceflinger/TimeStats/TimeStats.h
index a87b7cb..5b0f5bd 100644
--- a/services/surfaceflinger/TimeStats/TimeStats.h
+++ b/services/surfaceflinger/TimeStats/TimeStats.h
@@ -29,9 +29,6 @@
 
 #include <../Fps.h>
 #include <gui/JankInfo.h>
-#include <stats_event.h>
-#include <stats_pull_atom_callback.h>
-#include <statslog.h>
 #include <timestatsproto/TimeStatsHelper.h>
 #include <timestatsproto/TimeStatsProtoHeader.h>
 #include <ui/FenceTime.h>
@@ -54,9 +51,8 @@
 
     virtual ~TimeStats() = default;
 
-    // Called once boot has been finished to perform additional capabilities,
-    // e.g. registration to statsd.
-    virtual void onBootFinished() = 0;
+    // Process a pull request from statsd.
+    virtual bool onPullAtom(const int atomId, std::string* pulledData);
 
     virtual void parseArgs(bool asProto, const Vector<String16>& args, std::string& result) = 0;
     virtual bool isEnabled() = 0;
@@ -232,58 +228,11 @@
 
 public:
     TimeStats();
-
-    // Delegate to the statsd service and associated APIs.
-    // Production code may use this class directly, whereas unit test may define
-    // a subclass for ease of testing.
-    class StatsEventDelegate {
-    public:
-        virtual ~StatsEventDelegate() = default;
-        virtual AStatsEvent* addStatsEventToPullData(AStatsEventList* data) {
-            return AStatsEventList_addStatsEvent(data);
-        }
-        virtual void setStatsPullAtomCallback(int32_t atom_tag,
-                                              AStatsManager_PullAtomMetadata* metadata,
-                                              AStatsManager_PullAtomCallback callback,
-                                              void* cookie) {
-            return AStatsManager_setPullAtomCallback(atom_tag, metadata, callback, cookie);
-        }
-
-        virtual void clearStatsPullAtomCallback(int32_t atom_tag) {
-            return AStatsManager_clearPullAtomCallback(atom_tag);
-        }
-
-        virtual void statsEventSetAtomId(AStatsEvent* event, uint32_t atom_id) {
-            return AStatsEvent_setAtomId(event, atom_id);
-        }
-
-        virtual void statsEventWriteInt32(AStatsEvent* event, int32_t field) {
-            return AStatsEvent_writeInt32(event, field);
-        }
-
-        virtual void statsEventWriteInt64(AStatsEvent* event, int64_t field) {
-            return AStatsEvent_writeInt64(event, field);
-        }
-
-        virtual void statsEventWriteString8(AStatsEvent* event, const char* field) {
-            return AStatsEvent_writeString(event, field);
-        }
-
-        virtual void statsEventWriteByteArray(AStatsEvent* event, const uint8_t* buf,
-                                              size_t numBytes) {
-            return AStatsEvent_writeByteArray(event, buf, numBytes);
-        }
-
-        virtual void statsEventBuild(AStatsEvent* event) { return AStatsEvent_build(event); }
-    };
     // For testing only for injecting custom dependencies.
-    TimeStats(std::unique_ptr<StatsEventDelegate> statsDelegate,
-              std::optional<size_t> maxPulledLayers,
+    TimeStats(std::optional<size_t> maxPulledLayers,
               std::optional<size_t> maxPulledHistogramBuckets);
 
-    ~TimeStats() override;
-
-    void onBootFinished() override;
+    bool onPullAtom(const int atomId, std::string* pulledData) override;
     void parseArgs(bool asProto, const Vector<String16>& args, std::string& result) override;
     bool isEnabled() override;
     std::string miniDump() override;
@@ -332,11 +281,8 @@
     static const size_t MAX_NUM_TIME_RECORDS = 64;
 
 private:
-    static AStatsManager_PullAtomCallbackReturn pullAtomCallback(int32_t atom_tag,
-                                                                 AStatsEventList* data,
-                                                                 void* cookie);
-    AStatsManager_PullAtomCallbackReturn populateGlobalAtom(AStatsEventList* data);
-    AStatsManager_PullAtomCallbackReturn populateLayerAtom(AStatsEventList* data);
+    bool populateGlobalAtom(std::string* pulledData);
+    bool populateLayerAtom(std::string* pulledData);
     bool recordReadyLocked(int32_t layerId, TimeRecord* timeRecord);
     void flushAvailableRecordsToStatsLocked(int32_t layerId, Fps displayRefreshRate,
                                             std::optional<Fps> renderRate,
@@ -366,7 +312,6 @@
     static const size_t RENDER_RATE_BUCKET_WIDTH = REFRESH_RATE_BUCKET_WIDTH;
     static const size_t MAX_NUM_LAYER_STATS = 200;
     static const size_t MAX_NUM_PULLED_LAYERS = MAX_NUM_LAYER_STATS;
-    std::unique_ptr<StatsEventDelegate> mStatsDelegate = std::make_unique<StatsEventDelegate>();
     size_t mMaxPulledLayers = MAX_NUM_PULLED_LAYERS;
     size_t mMaxPulledHistogramBuckets = 6;
 };