Avoid rebuilds after changes of layouts xml-files

This commit makes IC react more granularly on these changes
Precisely, it marks dirty only kt-files that having lookups into
synthetic package built upon a changed layout-file

 #KT-21622 Fixed

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/AbstractKotlinAndroidGradleTests.kt

@@ -1,6 +1,7 @@
 package org.jetbrains.kotlin.gradle
 
 import org.jetbrains.kotlin.gradle.util.getFileByName
+import org.jetbrains.kotlin.gradle.util.getFilesByNames
 import org.jetbrains.kotlin.gradle.util.isLegacyAndroidGradleVersion
 import org.jetbrains.kotlin.gradle.util.modify
 import org.junit.Test
@@ -212,6 +213,32 @@ fun getSomething() = 10
         }
     }
 
+    @Test
+    fun testAndroidExtensionsIncremental() {
+        val project = Project("AndroidExtensionsProject", gradleVersion)
+        val options = defaultBuildOptions().copy(incremental = true)
+
+        project.build("assembleDebug", options = options) {
+            assertSuccessful()
+            val affectedSources = project.projectDir.getFilesByNames(
+                    "MyActivity.kt", "noLayoutUsages.kt"
+            )
+            val relativePaths = project.relativize(affectedSources)
+            assertCompiledKotlinSources(relativePaths)
+        }
+
+        val activityLayout = project.projectFile("activity_main.xml")
+        activityLayout.modify { it.replace("textView", "newTextView") }
+
+        project.build("assembleDebug", options = options) {
+            assertFailed()
+            val affectedSources = project.projectDir.getFilesByNames("MyActivity.kt")
+            val relativePaths = project.relativize(affectedSources)
+            assertCompiledKotlinSources(relativePaths)
+        }
+    }
+
+
     @Test
     fun testAndroidExtensionsManyVariants() {
         val project = Project("AndroidExtensionsManyVariants", gradleVersion)

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/AndroidExtensionsProject/app/src/main/java/com/example/androidextensions/MyActivity.kt

@@ -22,6 +22,7 @@ import kotlinx.android.synthetic.main.activity_main.textView
 
 class HomeActivity : Activity() {
     override fun onCreate(savedInstanceState: Bundle?) {
+        myUtilFunction()
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
         

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/AndroidExtensionsProject/app/src/main/java/com/example/androidextensions/noLayoutUsages.kt

@@ -0,0 +1,3 @@
+package com.example.androidextensions
+
+fun myUtilFunction() = "OK"