Use font from external/noto-fonts/emoji-compat

Update EmojiCompat modules to reference the following files in 
external/noto-fonts/emoji-compat
- NotoColorEmojiCompat.ttf
- emojis.txt (used for testing)
- flatbuffers jar
- java files used to read binary FlatBuffers metadata in the font

Test: 
- ./gradlew support-emoji:connectedAndroidTest to see that the code works.
- ./gradlew uploadArchives to see that AAR’s are generated
- Inspected the AAR files to see that they contain font and the license 
files.

Bug: 36385743
Change-Id: Ib389e8abfb688af50aa1d40b26e6e455e3a50b99
diff --git a/emoji/bundled/build.gradle b/emoji/bundled/build.gradle
index f75d7d9..37d831d 100644
--- a/emoji/bundled/build.gradle
+++ b/emoji/bundled/build.gradle
@@ -1,6 +1,11 @@
 apply plugin: android.support.SupportLibraryPlugin
 archivesBaseName = 'support-emoji-bundled'
 
+ext {
+    File externalRoot = new File(rootDir, '../../external')
+    emojiCompatFontDir = externalRoot.absolutePath + '/noto-fonts/emoji-compat'
+}
+
 android {
     compileSdkVersion project.ext.currentSdk
 
@@ -10,7 +15,7 @@
 
     sourceSets {
         main.java.srcDir 'src'
-        main.assets.srcDirs 'assets'
+        main.assets.srcDirs "$emojiCompatFontDir/font"
     }
 }