Android: Remove apk modules for Android Studio

docs/android_studio.md

 # Android Studio
 
 [TOC]
 
 ## Usage
 
 Make sure you have followed
 [android build instructions](android_build_instructions.md) already.
 
 ```shell
 build/android/gradle/generate_gradle.py
 ```
 
 This creates a project at `out/Debug/gradle`. To create elsewhere:
 
 ```shell
 build/android/gradle/generate_gradle.py --output-directory out/My-Out-Dir --project-dir my-project
 ```
 
 By default, common targets are generated. To add more targets to generate
 projects for:
 
 ```shell
 build/android/gradle/generate_gradle.py --extra-target //chrome/android:chrome_public_apk
 ```
 
-For those upgrading from Android Studio 2.2 to 2.3:
-
-* Use `gn clean` and `gn gen`
-* Clean up in `//third_party/android_tools` with `git clean -ffd`.
-* Remove project from android studio and regenerate with `generate_gradle.py`.
-
 For first-time Android Studio users:
 
 * Avoid running the setup wizard.
     * The wizard will force you to download unwanted SDK components to
       `//third_party/android_tools`.
     * To skip it, select "Cancel" when it comes up.
 
+For those upgrading from Android Studio 2.2 to 2.3:
+
+* Use `gn clean` and `gn gen`
+* Clean up in `//third_party/android_tools` with `git clean -ffd`.
+* Remove project from android studio and regenerate with `generate_gradle.py`.
+
 To import the project:
 
 * Use "Import Project", and select the directory containing the generated
   project, by default `out/Debug/gradle`.
 
 You need to re-run `generate_gradle.py` whenever `BUILD.gn` files change.
 
 * After regenerating, Android Studio should prompt you to "Sync". If it
   doesn't, use:
     * Button with two arrows on the right side of the top strip.
     * Help -> Find Action -> "Sync Project with Gradle Files"
     * After `gn clean` you may need to restart Android Studio.
 
 ## How It Works
 
-Android Studio integration works by generating `build.gradle` files based on GN
-targets. Each valid target produces a separate Gradle sub-project.
-Instrumentation tests are combined with their `apk_under_test`.
+By default, only a single module is generated. If more than one apk target is
+specified, then an `_all` module is generated. Otherwise a single apk module is
+generated. Since instrumentation tests are combined with their `apk_under_test`
+target, they count as one module together.
+
+To see more detailed structure of gn targets, the `--split-projects` flag can
+be used. This will generate one module for every gn target in the dependency
+graph.
 
 ### Excluded Files
 
 Gradle supports source directories but not source files. However, files in
 Chromium are used amongst multiple targets. To accommodate this, the script
 detects such targets and creates exclude patterns to exclude files not in the
 current target. The editor does not respect these exclude patterns, so a `_all`
 pseudo module is added which includes directories from all targets. This allows
 imports and refactorings to be searched across all targets.
 
@@ skipping 52 matching lines @@
 
 The resulting artifacts are not terribly useful. They are missing assets,
 resources, native libraries, etc.
 
 * Use a
   [gradle daemon](https://docs.gradle.org/2.14.1/userguide/gradle_daemon.html)
   to speed up builds using the gradlew script:
     * Add the line `org.gradle.daemon=true` to `~/.gradle/gradle.properties`,
       creating it if necessary.
 
-## Status (as of April 19th, 2017)
+## Status (as of April 27th, 2017)
 
 ### What works
 
 * Android Studio v2.3.
 * Java editing and gradle compile.
 * Instrumentation tests included as androidTest.
 * Symlinks to existing .so files in jniLibs (doesn't generate them).
 * Editing resource xml files.
 * Java debugging (see
 [here](/docs/android_debugging_instructions.md#Android-Studio)).
 * Import resolution and refactoring across all modules.
+* Correct lint and AndroidManifest when only one target is specified.
 
 ### What doesn't work (yet) ([crbug](https://bugs.chromium.org/p/chromium/issues/detail?id=620034))
 
 * Gradle being aware of assets.
 * Layout editor.
 * Add support for native code editing.
 * Make the "Make Project" button work correctly.