Push Hidden_api inside HiddenAPIFlagFileProperties

All usages of HiddenAPIFlagFileProperties use it as the type of a
Hidden_api field. This change pushes the field inside the struct and
just embeds the struct inside the structs that need it making it
simpler and more consistent with how the HiddenApiPackageProperties
struct is used.

This is extracted as a separate change as while the change is simple
it does affect a lot of lines. Keeping it separate makes it easier to
review the changes.

Bug: 240406019
Test: packages/modules/common/build/mainline_modules_sdks.sh
      # Ran the previous command with and without this change to make
      # sure that this change does not change the sdk snapshot
      # contents.
Change-Id: I664453029574ef68dc5712f7bf137a1a6e78e864
(cherry picked from commit 9b61abbd840503dd9bd2eebf7fee8be627be4eb5)
Merged-In: I664453029574ef68dc5712f7bf137a1a6e78e864
diff --git a/java/bootclasspath_fragment.go b/java/bootclasspath_fragment.go
index d78918b..024c4fa 100644
--- a/java/bootclasspath_fragment.go
+++ b/java/bootclasspath_fragment.go
@@ -128,7 +128,7 @@
 	Coverage BootclasspathFragmentCoverageAffectedProperties
 
 	// Hidden API related properties.
-	Hidden_api HiddenAPIFlagFileProperties
+	HiddenAPIFlagFileProperties
 
 	// The list of additional stub libraries which this fragment's contents use but which are not
 	// provided by another bootclasspath_fragment.
@@ -825,7 +825,7 @@
 	input.gatherStubLibInfo(ctx, contents)
 
 	// Populate with flag file paths from the properties.
-	input.extractFlagFilesFromProperties(ctx, &b.properties.Hidden_api)
+	input.extractFlagFilesFromProperties(ctx, &b.properties.HiddenAPIFlagFileProperties)
 
 	// Populate with package rules from the properties.
 	input.extractPackageRulesFromProperties(&b.sourceOnlyProperties.HiddenAPIPackageProperties)