BootParameters: Use proto for disk io.

Use proto for disk usage.

Bug: 79932027
Test: Ran through the following scenarios-
- RebootActivity parses previous boot parameters; sets next as expected.
- Push old parameters to device and ensured bootanimations reads it and
saves new format (serialized proto) that can be read in userspace
(RebootActivity).
- Unit tests pass.

Change-Id: I98aefb7a832c985d5061ee80ab85a4523f067641
diff --git a/cmds/bootanimation/iot/BootParameters.h b/cmds/bootanimation/iot/BootParameters.h
index 49c34dd..cbd1ca6 100644
--- a/cmds/bootanimation/iot/BootParameters.h
+++ b/cmds/bootanimation/iot/BootParameters.h
@@ -22,7 +22,7 @@
 #include <vector>
 
 #include <boot_action/boot_action.h>  // libandroidthings native API.
-#include <json/json.h>
+#include <boot_parameters.pb.h>
 
 namespace android {
 
@@ -39,22 +39,33 @@
     // Returns the additional boot parameters that were set on reboot.
     const std::vector<ABootActionParameter>& getParameters() const { return mParameters; }
 
-    // Exposed for testing. Updates the parameters with new JSON values.
-    void loadParameters(const std::string& raw_json);
-private:
+    // Exposed for testing. Sets the parameters to the serialized proto.
+    void parseBootParameters(const std::string &contents);
+
+    // For devices that OTA from N to O.
+    // Exposed for testing. Sets the parameters to the raw JSON.
+    void parseLegacyBootParameters(const std::string &contents);
+
+    // Exposed for testing. Loads the contents from |nextBootFile| and replaces
+    // |lastBootFile| with |nextBootFile|.
+    static bool swapAndLoadBootConfigContents(const char *lastBootFile, const char *nextBootFile,
+                                              std::string *contents);
+
+  private:
     void loadParameters();
 
-    void parseBootParameters();
+    // Replaces the legacy JSON blob with the updated version, allowing the
+    // framework to read it.
+    void storeParameters();
+
+    void loadStateFromProto();
 
     bool mIsSilentBoot = false;
 
     std::vector<ABootActionParameter> mParameters;
 
-    // Store parsed JSON because mParameters makes a shallow copy.
-    Json::Value mJson;
-
-    // Store parameter keys because mParameters makes a shallow copy.
-    Json::Value::Members mKeys;
+    // Store the proto because mParameters makes a shallow copy.
+    android::things::proto::BootParameters mProto;
 };
 
 }  // namespace android