generate_gradle.py: Take compile_sdk_version and min_sdk_version from GN

* Always use public compileSdkVersion to avoid issues with pre-release
SDKs.
* Use default minSdkVersion since we don't currently care about
  per-target minSdkVersion

Bug: 1335494
Change-Id: I951dd64d156cc9d1729b749fddf5a192b56f8e98
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3715252
Auto-Submit: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Peter Wen <wnwen@chromium.org>
Commit-Queue: Peter Wen <wnwen@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1015989}

build/android/gradle/android.jinja

@@ -51,7 +51,7 @@ android {
 
     defaultConfig {
         vectorDrawables.useSupportLibrary = true
-        minSdkVersion 21
+        minSdkVersion {{ min_sdk_version }}
         targetSdkVersion {{ target_sdk_version }}
     }
 

build/android/gradle/generate_gradle.py

@@ -511,12 +511,14 @@ def _GenerateGradleProperties():
 
 def _GenerateBaseVars(generator, build_vars):
   variables = {}
-  variables['compile_sdk_version'] = (
-      'android-%s' % build_vars['compile_sdk_version'])
-  target_sdk_version = build_vars['android_sdk_version']
+  # Avoid pre-release SDKs since Studio might not know how to download them.
+  variables['compile_sdk_version'] = ('android-%s' %
+                                      build_vars['public_android_sdk_version'])
+  target_sdk_version = build_vars['public_android_sdk_version']
   if str(target_sdk_version).isalpha():
     target_sdk_version = '"{}"'.format(target_sdk_version)
   variables['target_sdk_version'] = target_sdk_version
+  variables['min_sdk_version'] = build_vars['default_min_sdk_version']
   variables['use_gradle_process_resources'] = (
       generator.use_gradle_process_resources)
   variables['channel'] = generator.channel
@@ -757,12 +759,6 @@ def main():
                       action='append',
                       help='GN native targets to generate for. May be '
                            'repeated.')
-  parser.add_argument('--compile-sdk-version',
-                      type=int,
-                      default=32,
-                      help='Override compileSdkVersion for android sdk docs. '
-                           'Useful when sources for android_sdk_version is '
-                           'not available in Android Studio.')
   parser.add_argument(
       '--sdk-path',
       default=os.path.expanduser('~/Android/Sdk'),
@@ -832,9 +828,6 @@ def main():
     channel = 'canary'
   else:
     channel = 'stable'
-  # Don't take compile_sdk_version from build_vars since pre-release SDKs can
-  # cause Android Studio to have issues.
-  build_vars['compile_sdk_version'] = args.compile_sdk_version
   generator = _ProjectContextGenerator(_gradle_output_dir, build_vars,
       args.use_gradle_process_resources, jinja_processor, args.split_projects,
       channel)

build/config/android/build_vars.gni

@@ -17,7 +17,9 @@ android_build_vars_json = {
     android_sdk_root = rebase_path(android_sdk_root, root_build_dir)
     android_sdk_version = android_sdk_version
     android_tool_prefix = rebase_path(android_tool_prefix, root_build_dir)
+    default_min_sdk_version = default_min_sdk_version
     final_android_sdk = final_android_sdk
+    public_android_sdk_version = public_android_sdk_version
 
     if (defined(android_secondary_abi_cpu)) {
       android_secondary_abi_toolchain =

build/config/android/config.gni

@@ -107,9 +107,10 @@ if (is_android || is_chromeos) {
   public_android_sdk_root = "//third_party/android_sdk/public"
   public_android_sdk_build_tools =
       "${public_android_sdk_root}/build-tools/31.0.0"
+  public_android_sdk_version = "31"
   if (android_sdk_release == "s") {
     default_android_sdk_root = public_android_sdk_root
-    default_android_sdk_version = "31"
+    default_android_sdk_version = public_android_sdk_version
     default_android_sdk_build_tools_version = "31.0.0"
     public_android_sdk = true
   }

docs/android_studio.md

@@ -38,21 +38,6 @@ available" notification.
     * After `gn clean` you may need to restart Android Studio.
     * File -> "Invalidate Caches / Restart..."
 
-## Troubleshooting
-
-If building the Gradle files in Android Studio prints an error like this:
-
-```
-Failed to find Platform SDK with path: platforms;android-31
-```
-
-Then it means the SDK is being updated to the new release. A workaround is to
-ask for an older SDK version in `args.gn`:
-
-```
-android_sdk_version = 30
-```
-
 ## How It Works
 
 By default, only an `_all` module containing all java apk targets is generated.