Fix a bug in core_settings.gradle with relative paths

I think this has been broken since https://github.com/google/ExoPlayer/commit/617267bfcf20c500fb4a3cfdff7104e4d88261a7 (which was trying to fix
the same problem).

This change initializes `rootDir` to always be the current project (i.e. ExoPlayer)
directory. From the [Gradle docs](https://docs.gradle.org/current/userguide/working_with_files.html#sec:single_file_paths):
> What happens in the case of multi-project builds? The file() method
> will always turn relative paths into paths that are relative to the
> current project directory, which may be a child project.

We can also then remove exoplayerRoot completely and simplify the local
dependency instructions.

* #minor-release
* #exofixit
* Issue: #9403

PiperOrigin-RevId: 395478121

README.md

@@ -115,9 +115,8 @@ Next, add the following to your project's `settings.gradle` file, replacing
 `path/to/exoplayer` with the path to your local copy:
 `path/to/exoplayer` with the path to your local copy:
 
 
 ```gradle
 ```gradle
-gradle.ext.exoplayerRoot = 'path/to/exoplayer'
 gradle.ext.exoplayerModulePrefix = 'exoplayer-'
 gradle.ext.exoplayerModulePrefix = 'exoplayer-'
-apply from: file("$gradle.ext.exoplayerRoot/core_settings.gradle")
+apply from: file("path/to/exoplayer/core_settings.gradle")
 ```
 ```
 
 
 You should now see the ExoPlayer modules appear as part of your project. You can
 You should now see the ExoPlayer modules appear as part of your project. You can

RELEASENOTES.md

@@ -9,6 +9,9 @@
     *   Fix `NullPointerException` being thrown from `CacheDataSource` when
     *   Fix `NullPointerException` being thrown from `CacheDataSource` when
         reading a fully cached resource with `DataSpec.position` equal to the
         reading a fully cached resource with `DataSpec.position` equal to the
         resource length.
         resource length.
+    *   Fix a bug when [depending on ExoPlayer locally](README.md#locally) with
+        a relative path
+        ([#9403](https://github.com/google/ExoPlayer/issues/9403)).
 *   Extractors:
 *   Extractors:
     *   Support TS packets without PTS flag
     *   Support TS packets without PTS flag
         ([#9294](https://github.com/google/ExoPlayer/issues/9294)).
         ([#9294](https://github.com/google/ExoPlayer/issues/9294)).

core_settings.gradle

@@ -11,7 +11,7 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // See the License for the specific language governing permissions and
 // limitations under the License.
 // limitations under the License.
-def rootDir = file(gradle.ext.exoplayerRoot)
+def rootDir = file(".")
 if (!gradle.ext.has('exoplayerSettingsDir')) {
 if (!gradle.ext.has('exoplayerSettingsDir')) {
     gradle.ext.exoplayerSettingsDir = rootDir.getCanonicalPath()
     gradle.ext.exoplayerSettingsDir = rootDir.getCanonicalPath()
 }
 }

settings.gradle

@@ -11,7 +11,6 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // See the License for the specific language governing permissions and
 // limitations under the License.
 // limitations under the License.
-gradle.ext.exoplayerRoot = rootDir
 gradle.ext.exoplayerModulePrefix = ''
 gradle.ext.exoplayerModulePrefix = ''
 
 
 def modulePrefix = ':'
 def modulePrefix = ':'