Android: Update Android Studio docs

Be more explicit that it is ok to accept Android Studio's recommended
actions. Update various sections to the current status quo, clarify
which options are supported and which are deprecated, and delete
sections that are no longer relevant.

Bug: 1401205
Change-Id: I1799b9674b1702a8c617d1560efee8999dc53f07
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4206029
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Auto-Submit: Peter Wen <wnwen@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1099060}

docs/android_studio.md

@@ -21,18 +21,17 @@ To import the project:
 See [android_test_instructions.md](testing/android_test_instructions.md#Using-Emulators)
 for more information about building and running emulators.
 
-If you're asked to use Studio's Android SDK: No.
-
-If you're asked to use Studio's Gradle wrapper: Yes.
-
-You need to re-run `generate_gradle.py` whenever `BUILD.gn` files change, for
-example, when you add a new directory containing source files.
-
-Since newer gradle versions are released regularly and it is not possible to set
-a gradle version in `root.jinja` that is the newest for each version of Android
-Studio, feel free to update the value in `build.gradle` locally when you see the
-"A newer version of gradle is available" notification. This will likely happen
-each time after `generate_gradle.py` runs.
+Feel free to accept Android Studio's recommended actions. `generate_gradle.py`
+should have already set up a working version of the gradle wrapper and the
+android gradle plugin, as well as a default Android SDK location at
+`~/Android/Sdk`. Since the same script needs to support various versions of
+Android Studio, the defaults may have lower version than the one recommended by
+your version of Android Studio. After you accept Android Studio's update actions
+the `generate_gradle.py` script will try to keep the newer versions when it is
+re-run.
+
+You'll need to re-run `generate_gradle.py` whenever new directories containing
+source files are added.
 
 * After regenerating, Android Studio should prompt you to "Sync". If it
   doesn't, try some of the following options:
@@ -48,40 +47,25 @@ By default, only an `_all` module containing all java apk targets is generated.
 If just one apk target is explicitly specified, then a single apk module is
 generated.
 
-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. This can be very slow.
-
-### Excluded Files
+If you really prefer a more detailed structure of gn targets, the deprecated
+`--split-projects` flag can be used. This will generate one module for every gn
+target in the dependency graph. This can be very slow and is no longer
+supported.
 
-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 the
-`_all` pseudo module is added which includes directories from all targets. This
-allows imports and refactoring to be across all targets.
-
-### Extracting .srcjars
+### Generated files
 
 Most generated .java files in GN are stored as `.srcjars`. Android Studio does
-not support them. The generator script builds and extracts them to
-`extracted-srcjars/` subdirectories for each target that contains generated
-files. This is the reason that the `_all` pseudo module may contain multiple
-copies of generated files. It can be slow to build all these generated files,
-so if `--fast` is passed then the generator script skips building and
-extracting them.
-
-*** note
-** TLDR:** Always re-generate project files when generated files change (this
-includes `R.java`).
-***
+not support them. Our build will automatically extract them to a
+`generated_java` directory in the output directory during the build. Thus if a
+generated file is missing in Android Studio, build it with ninja first and it
+should show up in Android Studio afterwards.
 
 ### Native Files
 
-This option is no longer supported since Android Studio is very slow when
-editing in a code base with a large number of C++ files, and Chromium has a lot
-of C++ code. It is recommended to use [VS Code](vscode.md) to edit native files
-and stick to just editing java files in Android Studio.
+This option is deprecated and no longer supported since Android Studio is very
+slow when editing in a code base with a large number of C++ files, and Chromium
+has a lot of C++ code. It is recommended to use [VS Code](vscode.md) to edit
+native files and stick to just editing java files in Android Studio.
 
 If you still want to enable editing native C/C++ files with Android Studio, pass
 in any number of `--native-target [target name]` flags in order to use it. The
@@ -110,12 +94,13 @@ build/android/gradle/generate_gradle.py --native-target //chrome/android:libchro
 * Use environment variables to avoid having to specify `--output-directory`.
     * Example: Append `export CHROMIUM_OUT_DIR=out; export BUILDTYPE=Debug` to
       your `~/.bashrc` to always default to `out/Debug`.
-* Using the Java debugger is documented [here](android_debugging_instructions.md#android-studio).
+* Using the Java debugger is documented
+  [here](android_debugging_instructions.md#android-studio).
 * Configuration instructions can be found
   [here](http://tools.android.com/tech-docs/configuration). One suggestions:
     * Launch it with more RAM:
       `STUDIO_VM_OPTIONS=-Xmx2048m /opt/android-studio-stable/bin/studio-launcher.sh`
-* If you ever need to reset it: `rm -r ~/.AndroidStudio*/`
+* If you ever need to reset it: `rm -r ~/.config/Google/AndroidStudio*/`
 * Import Chromium-specific style and inspections settings:
     * Help -> Find Action -> "Code Style" (settings) -> Java ->
       Scheme -> Import Scheme
@@ -155,28 +140,16 @@ build/android/gradle/generate_gradle.py --native-target //chrome/android:libchro
 * `Alt + Enter`: Quick Fix (use on underlined errors)
 * `F2`: Find next error
 
-### Building from the Command Line
-
-Gradle builds can be done from the command-line after importing the project
-into Android Studio (importing into the IDE causes the Gradle wrapper to be
-added). This wrapper can also be used to invoke gradle commands.
-
-    cd $GRADLE_PROJECT_DIR && bash gradlew
-
-The resulting artifacts are not terribly useful. They are missing assets,
-resources, native libraries, etc.
+### Building with Gradle
 
-* 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.
+Gradle builds are not supported. Only editing is supported in Android Studio.
+Use ninja to build as usual.
 
 ## Status
 
 ### What works
 
-* Android Studio v2021 & v2022.
+* Android Studio v2021~v2023.
 * Java editing.
     * Application code in `main` sourceset.
     * Instrumentation test code in `androidTest` sourceset.
@@ -187,14 +160,12 @@ resources, native libraries, etc.
 * Java debugging (see
 [here](/docs/android_debugging_instructions.md#Android-Studio)).
 * Import resolution and refactoring across java files.
-* Correct lint and AndroidManifest when only one target is specified.
-* Emulators (more docs coming soon).
 * Separate Android SDK for Android Studio.
 
 ### What doesn't work
 
-* Gradle being aware of assets.
-* Having the "Make Project" button work correctly.
+* Building with Gradle.
+* The "Make Project" button doesn't work.
     * Stick to using `autoninja` to build targets and just use Android Studio
       for editing java source files.
 * No active work is underway or planned to expand Android Studio support.