Generate Javadoc for each module individually

Notes:
- The VP9 one is failing claiming that the util package
  doesn't exist and that LibraryLoader cannot be found.
  Unsure why, since it appears to be setup exactly like
  other extensions (e.g. Opus) that does work.
- @link across modules will not work when generating
  Javadoc for a single module. This is WAI. I subsequent
  change will add an aggregated Javadoc generator that
  will generate Javadoc for all modules together and
  apply cross module @link correctly.

Issue: #2139

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=150864273

extensions/cronet/build.gradle

@@ -39,3 +39,8 @@ dependencies {
     androidTestCompile project(':library')
     androidTestCompile 'com.android.support.test:runner:0.5'
 }
+
+ext {
+    javadocTitle = 'Cronet extension'
+}
+apply from: '../../library_javadoc.gradle'

extensions/ffmpeg/build.gradle

@@ -32,3 +32,8 @@ android {
 dependencies {
     compile project(':library-core')
 }
+
+ext {
+    javadocTitle = 'FFmpeg extension'
+}
+apply from: '../../library_javadoc.gradle'

extensions/flac/build.gradle

@@ -34,3 +34,7 @@ dependencies {
     androidTestCompile project(':testutils')
 }
 
+ext {
+    javadocTitle = 'FLAC extension'
+}
+apply from: '../../library_javadoc.gradle'

extensions/gvr/build.gradle

@@ -28,6 +28,11 @@ dependencies {
     compile 'com.google.vr:sdk-audio:1.30.0'
 }
 
+ext {
+    javadocTitle = 'GVR extension'
+}
+apply from: '../../library_javadoc.gradle'
+
 ext {
     releaseArtifact = 'extension-gvr'
     releaseDescription = 'Google VR extension for ExoPlayer.'

extensions/okhttp/build.gradle

@@ -35,6 +35,11 @@ dependencies {
     }
 }
 
+ext {
+    javadocTitle = 'OkHttp extension'
+}
+apply from: '../../library_javadoc.gradle'
+
 ext {
     releaseArtifact = 'extension-okhttp'
     releaseDescription = 'OkHttp extension for ExoPlayer.'

extensions/opus/build.gradle

@@ -32,3 +32,8 @@ android {
 dependencies {
     compile project(':library-core')
 }
+
+ext {
+    javadocTitle = 'Opus extension'
+}
+apply from: '../../library_javadoc.gradle'

extensions/vp9/build.gradle

@@ -33,3 +33,7 @@ dependencies {
     compile project(':library-core')
 }
 
+ext {
+    javadocTitle = 'VP9 extension'
+}
+apply from: '../../library_javadoc.gradle'

library/all/build.gradle

@@ -33,39 +33,6 @@ dependencies {
     compile project(':library-ui')
 }
 
-android.libraryVariants.all { variant ->
-    def name = variant.buildType.name
-    if (name.equals(BuilderConstants.DEBUG)) {
-        return; // Skip debug builds.
-    }
-    def task = project.tasks.create "jar${name.capitalize()}", Jar
-    task.dependsOn variant.javaCompile
-    task.from variant.javaCompile.destinationDir
-    artifacts.add('archives', task);
-}
-
-android.libraryVariants.all { variant ->
-    task("generate${variant.name.capitalize()}Javadoc", type: Javadoc) {
-        title = "ExoPlayer library"
-        description "Generates Javadoc for $variant.name."
-        source = variant.javaCompile.source
-        classpath = files(variant.javaCompile.classpath.files, project.android.getBootClasspath())
-        options {
-            links "http://docs.oracle.com/javase/7/docs/api/"
-            linksOffline "https://developer.android.com/reference","${android.sdkDirectory}/docs/reference"
-            encoding = 'UTF-8'
-        }
-        exclude '**/BuildConfig.java'
-        exclude '**/R.java'
-        doLast {
-            copy {
-                from "src/main/javadoc"
-                into "$buildDir/docs/javadoc"
-            }
-        }
-    }
-}
-
 ext {
     releaseArtifact = 'exoplayer'
     releaseDescription = 'The ExoPlayer library (all modules).'

library/core/build.gradle

@@ -45,6 +45,11 @@ dependencies {
     androidTestCompile 'org.mockito:mockito-core:1.9.5'
 }
 
+ext {
+    javadocTitle = 'Core'
+}
+apply from: '../../library_javadoc.gradle'
+
 ext {
     releaseArtifact = 'exoplayer-core'
     releaseDescription = 'The ExoPlayer library core module.'

library/dash/build.gradle

@@ -37,6 +37,11 @@ dependencies {
     androidTestCompile 'org.mockito:mockito-core:1.9.5'
 }
 
+ext {
+    javadocTitle = 'DASH'
+}
+apply from: '../../library_javadoc.gradle'
+
 ext {
     releaseArtifact = 'exoplayer-dash'
     releaseDescription = 'The ExoPlayer library DASH module.'

library/hls/build.gradle

@@ -31,6 +31,11 @@ dependencies {
     androidTestCompile 'org.mockito:mockito-core:1.9.5'
 }
 
+ext {
+    javadocTitle = 'HLS'
+}
+apply from: '../../library_javadoc.gradle'
+
 ext {
     releaseArtifact = 'exoplayer-hls'
     releaseDescription = 'The ExoPlayer library HLS module.'

library/smoothstreaming/build.gradle

@@ -37,6 +37,11 @@ dependencies {
     androidTestCompile 'org.mockito:mockito-core:1.9.5'
 }
 
+ext {
+    javadocTitle = 'SmoothStreaming'
+}
+apply from: '../../library_javadoc.gradle'
+
 ext {
     releaseArtifact = 'exoplayer-smoothstreaming'
     releaseDescription = 'The ExoPlayer library SmoothStreaming module.'

library/ui/build.gradle

@@ -28,6 +28,11 @@ dependencies {
     compile 'com.android.support:support-annotations:25.2.0'
 }
 
+ext {
+    javadocTitle = 'UI'
+}
+apply from: '../../library_javadoc.gradle'
+
 ext {
     releaseArtifact = 'exoplayer-ui'
     releaseDescription = 'The ExoPlayer library UI module.'

library_javadoc.gradle

@@ -0,0 +1,34 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+android.libraryVariants.all { variant ->
+    task("generate${variant.name.capitalize()}Javadoc", type: Javadoc) {
+        description "Generates Javadoc for $variant.name."
+        title = javadocTitle
+        source = variant.javaCompile.source
+        classpath = files(variant.javaCompile.classpath.files, project.android.getBootClasspath())
+        options {
+            links "http://docs.oracle.com/javase/7/docs/api/"
+            linksOffline "https://developer.android.com/reference","${android.sdkDirectory}/docs/reference"
+            encoding = 'UTF-8'
+        }
+        exclude '**/BuildConfig.java'
+        exclude '**/R.java'
+        doLast {
+            copy {
+                from "src/main/javadoc"
+                into "$buildDir/docs/javadoc"
+            }
+        }
+    }
+}