[AU] Import gain setting into ports

    Review: https://partner-android-review.git.corp.google.com/#/c/183780

    Signed-off-by: Hochi Huang <hochi.huang@mediatek.com>

Change-Id: I415d0b494b9bfadf783280aeea6ad46e0a242cfb
diff --git a/services/audiopolicy/AudioPolicyManager.cpp b/services/audiopolicy/AudioPolicyManager.cpp
index e18f470..c437551 100644
--- a/services/audiopolicy/AudioPolicyManager.cpp
+++ b/services/audiopolicy/AudioPolicyManager.cpp
@@ -5852,12 +5852,28 @@
             }
         }
     }
+    for (size_t k = 0 ; k < port->mGains.size() ; k++) {
+        sp<AudioGain> gain = port->mGains.itemAt(k);
+        if (gain != 0) {
+            bool hasGain = false;
+            for (size_t l = 0 ; l < mGains.size() ; l++) {
+                if (gain == mGains.itemAt(l)) {
+                    hasGain = true;
+                    break;
+                }
+            }
+            if (!hasGain) { // never import a gain twice
+                mGains.add(gain);
+            }
+        }
+    }
 }
 
 void AudioPolicyManager::AudioPort::clearCapabilities() {
     mChannelMasks.clear();
     mFormats.clear();
     mSamplingRates.clear();
+    mGains.clear();
 }
 
 void AudioPolicyManager::AudioPort::loadSamplingRates(char *name)