Fix Jacoco coverage runner.

- Correctly set the version of Jacoco to use via classpath dependency in
  build.gradle as noted in JacocoOptions.java
- Move to using jacoco 0.7.8

Bug: 37475483
Test: ./gradlew assembleAndroidTest and locally verify that dist/ and test apks contain
      correct version of Jacoco.

Change-Id: I2577bdaf3d5ba31102191ac0048595e042513618

build.gradle

@@ -9,6 +9,7 @@ repos.addMavenRepositories(repositories)
 
 dependencies {
     compile libs.gradle
+    compile libs.jacoco
     compile libs.error_prone
     compile libs.jarjar_gradle
 }

dependencies.gradle

@@ -24,6 +24,7 @@ libs.junit = 'junit:junit:4.12'
 libs.test_runner = 'com.android.support.test:runner:0.6-alpha'
 libs.espresso_core = 'com.android.support.test.espresso:espresso-core:2.3-alpha'
 libs.espresso_contrib = 'com.android.support.test.espresso:espresso-contrib:2.3-alpha'
+libs.jacoco = 'org.jacoco:org.jacoco.core:0.7.8'
 
 def androidPluginVersionOverride = System.getenv("GRADLE_PLUGIN_VERSION")
 

src/main/groovy/android/support/SupportLibraryPlugin.groovy

@@ -59,12 +59,6 @@ class SupportLibraryPlugin implements Plugin<Project> {
             testInstrumentationRunner INSTRUMENTATION_RUNNER
         }
 
-        // A workaround for b.android.com/293641 where Android Gradle Plugin delays Jacoco
-        // dependency resolution if it is not set explicitly.
-        project.dependencies {
-            androidJacocoAnt "org.jacoco:org.jacoco.ant:0.7.5.201505241946"
-        }
-
         library.signingConfigs {
             debug {
                 // Use a local debug keystore to avoid build server issues.