JPEG/R: minor update for decoder.

Expose metadata for the decoder
Updata document
Rename "jpegr_metadata" to "jpegr_metadata_struct"

Bug: b/264715926
Test: jpegr_test

Change-Id: I6d97209453b2338996f5dc2aabfbdbe3e8a8c20c
diff --git a/libs/jpegrecoverymap/tests/recoverymapmath_test.cpp b/libs/jpegrecoverymap/tests/recoverymapmath_test.cpp
index 6c61ff1..cf6a034 100644
--- a/libs/jpegrecoverymap/tests/recoverymapmath_test.cpp
+++ b/libs/jpegrecoverymap/tests/recoverymapmath_test.cpp
@@ -554,8 +554,8 @@
 
 TEST_F(RecoveryMapMathTest, applyRecoveryLUT) {
   for (int boost = 1; boost <= 10; boost++) {
-    jpegr_metadata metadata = { .maxContentBoost = static_cast<float>(boost),
-                                .minContentBoost = 1.0f / static_cast<float>(boost) };
+    jpegr_metadata_struct metadata = { .maxContentBoost = static_cast<float>(boost),
+                                       .minContentBoost = 1.0f / static_cast<float>(boost) };
     RecoveryLUT recoveryLUT(&metadata);
     for (int idx = 0; idx < kRecoveryFactorNumEntries; idx++) {
       float value = static_cast<float>(idx) / static_cast<float>(kRecoveryFactorNumEntries - 1);
@@ -573,8 +573,8 @@
   }
 
   for (int boost = 1; boost <= 10; boost++) {
-    jpegr_metadata metadata = { .maxContentBoost = static_cast<float>(boost),
-                                .minContentBoost = 1.0f };
+    jpegr_metadata_struct metadata = { .maxContentBoost = static_cast<float>(boost),
+                                       .minContentBoost = 1.0f };
     RecoveryLUT recoveryLUT(&metadata);
     for (int idx = 0; idx < kRecoveryFactorNumEntries; idx++) {
       float value = static_cast<float>(idx) / static_cast<float>(kRecoveryFactorNumEntries - 1);
@@ -592,8 +592,8 @@
   }
 
   for (int boost = 1; boost <= 10; boost++) {
-    jpegr_metadata metadata = { .maxContentBoost = static_cast<float>(boost),
-                                .minContentBoost = 1.0f / pow(static_cast<float>(boost),
+    jpegr_metadata_struct metadata = { .maxContentBoost = static_cast<float>(boost),
+                                       .minContentBoost = 1.0f / pow(static_cast<float>(boost),
                                                               1.0f / 3.0f) };
     RecoveryLUT recoveryLUT(&metadata);
     for (int idx = 0; idx < kRecoveryFactorNumEntries; idx++) {
@@ -659,8 +659,8 @@
 }
 
 TEST_F(RecoveryMapMathTest, EncodeRecovery) {
-  jpegr_metadata metadata = { .maxContentBoost = 4.0f,
-                              .minContentBoost = 1.0f / 4.0f };
+  jpegr_metadata_struct metadata = { .maxContentBoost = 4.0f,
+                                     .minContentBoost = 1.0f / 4.0f };
 
   EXPECT_EQ(encodeRecovery(0.0f, 0.0f, &metadata), 127);
   EXPECT_EQ(encodeRecovery(0.0f, 1.0f, &metadata), 127);
@@ -717,8 +717,8 @@
 }
 
 TEST_F(RecoveryMapMathTest, ApplyRecovery) {
-  jpegr_metadata metadata = { .maxContentBoost = 4.0f,
-                              .minContentBoost = 1.0f / 4.0f };
+  jpegr_metadata_struct metadata = { .maxContentBoost = 4.0f,
+                                     .minContentBoost = 1.0f / 4.0f };
 
   EXPECT_RGB_NEAR(applyRecovery(RgbBlack(), 0.0f, &metadata), RgbBlack());
   EXPECT_RGB_NEAR(applyRecovery(RgbBlack(), 0.5f, &metadata), RgbBlack());
@@ -981,8 +981,8 @@
 }
 
 TEST_F(RecoveryMapMathTest, ApplyMap) {
-  jpegr_metadata metadata = { .maxContentBoost = 8.0f,
-                              .minContentBoost = 1.0f / 8.0f };
+  jpegr_metadata_struct metadata = { .maxContentBoost = 8.0f,
+                                     .minContentBoost = 1.0f / 8.0f };
 
   EXPECT_RGB_EQ(Recover(YuvWhite(), 1.0f, &metadata),
                 RgbWhite() * 8.0f);