Update parameters' type from NSString to AVAudioSession*.

Bug: webrtc:15233
Change-Id: I110a3fb1e992ff07aebe21881ee31d55d39db60b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/308520
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#40258}
diff --git a/sdk/objc/components/audio/RTCAudioSession.h b/sdk/objc/components/audio/RTCAudioSession.h
index 729b5a2..2730664 100644
--- a/sdk/objc/components/audio/RTCAudioSession.h
+++ b/sdk/objc/components/audio/RTCAudioSession.h
@@ -225,14 +225,14 @@
 // AVAudioSession. `lockForConfiguration` must be called before using them
 // otherwise they will fail with kRTCAudioSessionErrorLockRequired.
 
-- (BOOL)setCategory:(NSString *)category
-               mode:(NSString *)mode
+- (BOOL)setCategory:(AVAudioSessionCategory)category
+               mode:(AVAudioSessionMode)mode
             options:(AVAudioSessionCategoryOptions)options
               error:(NSError **)outError;
-- (BOOL)setCategory:(NSString *)category
+- (BOOL)setCategory:(AVAudioSessionCategory)category
         withOptions:(AVAudioSessionCategoryOptions)options
               error:(NSError **)outError;
-- (BOOL)setMode:(NSString *)mode error:(NSError **)outError;
+- (BOOL)setMode:(AVAudioSessionMode)mode error:(NSError **)outError;
 - (BOOL)setInputGain:(float)gain error:(NSError **)outError;
 - (BOOL)setPreferredSampleRate:(double)sampleRate error:(NSError **)outError;
 - (BOOL)setPreferredIOBufferDuration:(NSTimeInterval)duration error:(NSError **)outError;
diff --git a/sdk/objc/components/audio/RTCAudioSession.mm b/sdk/objc/components/audio/RTCAudioSession.mm
index 2a6a202..f6b91d5 100644
--- a/sdk/objc/components/audio/RTCAudioSession.mm
+++ b/sdk/objc/components/audio/RTCAudioSession.mm
@@ -407,8 +407,8 @@
   return success;
 }
 
-- (BOOL)setCategory:(NSString *)category
-               mode:(NSString *)mode
+- (BOOL)setCategory:(AVAudioSessionCategory)category
+               mode:(AVAudioSessionMode)mode
             options:(AVAudioSessionCategoryOptions)options
               error:(NSError **)outError {
   if (![self checkLock:outError]) {
@@ -417,7 +417,7 @@
   return [self.session setCategory:category mode:mode options:options error:outError];
 }
 
-- (BOOL)setCategory:(NSString *)category
+- (BOOL)setCategory:(AVAudioSessionCategory)category
         withOptions:(AVAudioSessionCategoryOptions)options
               error:(NSError **)outError {
   if (![self checkLock:outError]) {
@@ -426,7 +426,7 @@
   return [self.session setCategory:category withOptions:options error:outError];
 }
 
-- (BOOL)setMode:(NSString *)mode error:(NSError **)outError {
+- (BOOL)setMode:(AVAudioSessionMode)mode error:(NSError **)outError {
   if (![self checkLock:outError]) {
     return NO;
   }