Make highmem classification of metalava optional

We have added a lot of metalava invocations since the highmem
differentation was added, most of which do not use a lot of memory.

By collecting data of max rss per process we have narrowed down
the set of highmem modules to a smaller set, and will annotate the
relevant modules as such.

Bug: 170701554
Test: NINJA_HIGHMEM_NUM_JOBS=3 m checkapi (no long tail of metalava)
Change-Id: Ic9c8c91388b02889111ef596fc6fd8bde9b42b9d
diff --git a/java/droiddoc.go b/java/droiddoc.go
index 344b15e..1e09d64 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -262,6 +262,10 @@
 	// TODO(b/146727827): Remove capability when we do not need to generate stubs and API separately.
 	Generate_stubs *bool
 
+	// if set to true, provides a hint to the build system that this rule uses a lot of memory,
+	// whicih can be used for scheduling purposes
+	High_mem *bool
+
 	// is set to true, Metalava will allow framework SDK to contain API levels annotations.
 	Api_levels_annotations_enabled *bool
 
@@ -1260,8 +1264,6 @@
 
 func metalavaCmd(ctx android.ModuleContext, rule *android.RuleBuilder, javaVersion javaVersion, srcs android.Paths,
 	srcJarList android.Path, bootclasspath, classpath classpath, sourcepaths android.Paths, implicitsRsp android.WritablePath, sandbox bool) *android.RuleBuilderCommand {
-	// Metalava uses lots of memory, restrict the number of metalava jobs that can run in parallel.
-	rule.HighMem()
 	cmd := rule.Command()
 	if ctx.Config().UseRBE() && ctx.Config().IsEnvTrue("RBE_METALAVA") {
 		rule.Remoteable(android.RemoteRuleSupports{RBE: true})
@@ -1343,6 +1345,11 @@
 
 	rule := android.NewRuleBuilder()
 
+	if BoolDefault(d.properties.High_mem, false) {
+		// This metalava run uses lots of memory, restrict the number of metalava jobs that can run in parallel.
+		rule.HighMem()
+	}
+
 	generateStubs := BoolDefault(d.properties.Generate_stubs, true)
 	var stubsDir android.OptionalPath
 	if generateStubs {