[IC] Allow to not specify the root project dir

When it's specified, it's used to calculate relative paths

compiler/daemon/daemon-common/src/org/jetbrains/kotlin/daemon/common/CompilationOptions.kt

@@ -73,7 +73,7 @@ class IncrementalCompilationOptions(
     /**
      * Root project directory, used to resolve relative paths
      */
-    val rootProjectDir: File,
+    val rootProjectDir: File?,
     kotlinScriptExtensions: Array<String>? = null,
     val withAbiSnapshot: Boolean = false,
     val preciseCompilationResultsBackup: Boolean = false,

compiler/daemon/src/org/jetbrains/kotlin/daemon/CompileServiceImpl.kt

@@ -559,8 +559,9 @@ abstract class CompileServiceImplBase(
         val modulesApiHistory = incrementalCompilationOptions.multiModuleICSettings?.run {
             val modulesInfo = incrementalCompilationOptions.modulesInfo
                 ?: error("The build is configured to use the history-file based IC approach, but doesn't provide the modulesInfo")
-
+            val rootProjectDir = incrementalCompilationOptions.rootProjectDir
-            ModulesApiHistoryJs(incrementalCompilationOptions.rootProjectDir, modulesInfo)
+                ?: error("rootProjectDir is expected to be non null when the history-file based IC approach is used")
+            ModulesApiHistoryJs(rootProjectDir, modulesInfo)
         } ?: EmptyModulesApiHistory
 
         val compiler = IncrementalJsCompilerRunner(
@@ -617,6 +618,9 @@ abstract class CompileServiceImplBase(
             reporter.info { "Use module detection: $useModuleDetection" }
             val modulesInfo = incrementalCompilationOptions.modulesInfo
                 ?: error("The build is configured to use the history-file based IC approach, but doesn't provide the modulesInfo")
+            check(projectRoot != null) {
+                "rootProjectDir is expected to be non null when the history-file based IC approach is used"
+            }
 
             if (!useModuleDetection) {
                 ModulesApiHistoryJvm(projectRoot, modulesInfo)

compiler/daemon/src/org/jetbrains/kotlin/daemon/report/BuildReportICReporter.kt

@@ -19,7 +19,7 @@ import java.io.File
 @VisibleForTesting
 class BuildReportICReporter(
     private val compilationResults: CompilationResults,
-    rootDir: File,
+    rootDir: File?,
     private val isVerbose: Boolean = false
 ) : ICReporterBase(rootDir), RemoteICReporter {
     private val icLogLines = arrayListOf<String>()

compiler/daemon/src/org/jetbrains/kotlin/daemon/report/DebugMessagesICReporter.kt

@@ -19,7 +19,7 @@ import java.io.File
 @VisibleForTesting
 class DebugMessagesICReporter(
     private val servicesFacade: CompilerServicesFacadeBase,
-    rootDir: File,
+    rootDir: File?,
     private val reportSeverity: ICReporter.ReportSeverity
 ) : ICReporterBase(rootDir), RemoteICReporter {