Add CMake path to gradle

platform_tools/android/apps/build.gradle

 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 
 buildscript {
     repositories {
         jcenter()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.1.0'
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
     }
 }
 
 allprojects {
     repositories {
         jcenter()
     }
 }
 
-def setupSkiaLibraryBuild(project, appVariants, buildCmd) {
+def setupSkiaLibraryBuild(project, appVariants, buildCmd, requireCMake = false) {
     appVariants.all{ variant ->
         def buildNativeLib = project.task("${variant.name}_SkiaNativeLib", type:Exec) {
             workingDir '../../../..' // top-level skia directory
             commandLine constructBuildCommand(variant, buildCmd).split()
-            environment PATH: getPathWithDepotTools()
+            environment PATH: getPathWithDeps(requireCMake)
             environment ANDROID_SDK_ROOT: getSDKPath()
         }
         buildNativeLib.onlyIf { !project.hasProperty("suppressNativeBuild") }
         TaskCollection<Task> compileTask = project.tasks.matching {
             //  println(it.name)
             it.name.toLowerCase().contains("compile" + variant.name.toLowerCase()) &&
                     it.name.toLowerCase().endsWith("ndk")
         }
         compileTask.getAt(0).dependsOn buildNativeLib
     }
@@ skipping 18 matching lines @@
         path = getLocalProperties().getProperty('sdk.dir', null)
     }
 
     if (path == null) {
         throw new GradleScriptException("Android SDK not found! Please set ANDROID_SDK_ROOT to" +
                                         " your path or define sdk.dir in gradle.properties")
     }
     return path
 }
 
-def getPathWithDepotTools() {
-    System.getenv("PATH") + ":" + getLocalProperties().getProperty('depot_tools.dir', null)
+def getPathWithDeps(requireCMake = false) {
     String path = System.getenv("PATH")
     if (!path.contains("depot_tools")) {
         path += ":" + getLocalProperties().getProperty('depot_tools.dir', null)
     }
 
     if (!path.contains("depot_tools")) {
         throw GradleScriptException("Depot Tools not found! Please update your path to include" +
                                     " depot_tools or define depot_tools.dir in gradle.properties")
     }
+
+    if (requireCMake) {
+        String cmakePath = getSDKPath() + "/cmake/bin"
+        if (!file(cmakePath).exists()) {
+            throw new GradleScriptException("cmake not found! Please install the android SDK version" +
+                                        " of cmake.", null);
+        }
+        if (!path.contains(cmakePath)) {
+            path = cmakePath + ":" + path
+        }
+    }
+
     return path
 }
 
 def constructBuildCommand(variant, buildTarget) {
     String cmdLine = "./platform_tools/android/bin/android_ninja $buildTarget"
     String deviceType = null
     if (variant.name.startsWith("arm64")) {
         deviceType = "arm64"
     } else if (variant.name.startsWith("arm")) {
         deviceType = "arm_v7_neon"
     } else if (variant.name.startsWith("x86_64")) {
         deviceType = "x86_64"
     } else if (variant.name.startsWith("x86")) {
         deviceType = "x86"
     } else if (variant.name.startsWith("mips")) {
         deviceType = "mips"
     } else if (variant.name.startsWith("mips64")) {
         deviceType = "mips64"
     }
 
     if (deviceType != null) {
         cmdLine += " -d " + deviceType
     }
 
     if (variant.name.endsWith("Release")) {
         cmdLine += " --release"
     }
     return cmdLine
 }