Put dependencies and their versions into one place.

Support library modules were hardcoding versions of each library
each each build.gradle file. This change moves all these to
buildSrc/dependencies.gradle so we can update the version in the
future with a single file change.

Test: ./gradlew clean assemble assembleAndroidTest still works.
Change-Id: I4238c1182c095ae80d1d6dbb751f71c0ddfe191f
diff --git a/wearable/build.gradle b/wearable/build.gradle
index 2102c4f..ddd04e8 100644
--- a/wearable/build.gradle
+++ b/wearable/build.gradle
@@ -4,20 +4,13 @@
 dependencies {
     compile project(':support-annotations')
     compile project(':support-core-ui')
-    androidTestCompile ("com.android.support.test:runner:${project.rootProject.ext.testRunnerVersion}") {
+
+    androidTestCompile (libs.test_runner) {
         exclude module: 'support-annotations'
     }
-    androidTestCompile ("com.android.support.test.espresso:espresso-core:${project.rootProject.ext.espressoVersion}") {
+    androidTestCompile (libs.espresso_core) {
         exclude module: 'support-annotations'
     }
-    testCompile 'junit:junit:4.12'
-    testCompile "org.mockito:mockito-core:1.9.5"
-    testCompile ("com.android.support.test:runner:${project.rootProject.ext.testRunnerVersion}") {
-        exclude module: 'support-annotations'
-    }
-    androidTestCompile "org.mockito:mockito-core:1.9.5"
-    androidTestCompile "com.google.dexmaker:dexmaker:1.2"
-    androidTestCompile "com.google.dexmaker:dexmaker-mockito:1.2"
 }
 
 android {