port more expressions/stages and integration tests

Author: wu-hui

firebase-firestore/src/androidTest/java/com/google/firebase/firestore/PipelineTest.java

@@ -599,7 +599,7 @@ public static void checkQueryAndPipelineResultsMatch(Query query, String... expe
     }
     PipelineSnapshot docsFromPipeline;
     try {
-      docsFromPipeline = waitFor(query.getFirestore().pipeline().convertFrom(query).execute());
+      docsFromPipeline = waitFor(query.getFirestore().pipeline().createFrom(query).execute());
     } catch (Exception e) {
       throw new RuntimeException("Pipeline FAILED", e);
     }

firebase-firestore/src/androidTest/java/com/google/firebase/firestore/QueryToPipelineTest.java

@@ -20,7 +20,7 @@
 import androidx.annotation.Nullable;
 import androidx.annotation.RestrictTo;
 import com.google.firebase.firestore.pipeline.AggregateFunction;
-import com.google.firebase.firestore.pipeline.AggregateWithAlias;
+import com.google.firebase.firestore.pipeline.AliasedAggregate;
 import java.util.Objects;
 
 /** Represents an aggregation that can be performed by Firestore. */
@@ -66,7 +66,7 @@ public String getOperator() {
   }
 
   @NonNull
-  abstract AggregateWithAlias toPipeline();
+  abstract AliasedAggregate toPipeline();
 
   /**
    * Returns true if the given object is equal to this object. Two `AggregateField` objects are
@@ -205,7 +205,7 @@ private CountAggregateField() {
 
     @NonNull
     @Override
-    AggregateWithAlias toPipeline() {
+    AliasedAggregate toPipeline() {
       return AggregateFunction.countAll().alias(getAlias());
     }
   }
@@ -218,7 +218,7 @@ private SumAggregateField(@NonNull FieldPath fieldPath) {
 
     @NonNull
     @Override
-    AggregateWithAlias toPipeline() {
+    AliasedAggregate toPipeline() {
       return field(getFieldPath()).sum().alias(getAlias());
     }
   }
@@ -231,7 +231,7 @@ private AverageAggregateField(@NonNull FieldPath fieldPath) {
 
     @NonNull
     @Override
-    AggregateWithAlias toPipeline() {
+    AliasedAggregate toPipeline() {
       return field(getFieldPath()).avg().alias(getAlias());
     }
   }

firebase-firestore/src/androidTest/java/com/google/firebase/firestore/testutil/IntegrationTestUtil.java

@@ -885,7 +885,11 @@ static void setClientLanguage(@NonNull String languageToken) {
   }
 
   /**
-   * Build a new Pipeline
+   * Builds a new Pipeline from this Firestore instance.
+   *
+   * NOTE: Pipeline does not have realtime updates support and SDK cache access, it completely relies
+   * on the connection to the server for the results, and does not augment the results with the SDK
+   * cache. To get realtime updates and SDK cache access use {@code realTimePipeline()} instead.
    *
    * @return {@code PipelineSource} for this Firestore instance.
    */
@@ -896,7 +900,13 @@ public PipelineSource pipeline() {
   }
 
   /**
-   * Build a new RealtimePipeline
+   * Build a new RealtimePipeline from this Firestore instance.
+   *
+   * NOTE: RealtimePipeline utilizes the Firestore realtime backend and SDK cache to provide final
+   * results, this is the equivalent to classic Firestore {@link Query}, but with more features
+   * supported. However, its feature set is only a subset of {@code Pipeline}. If you need features
+   * unavailable in {@code RealtimePipeline} and realtime or SDK cache access are not a must, use
+   * {@code pipeline()} instead.
    *
    * @return {@code RealtimePipelineSource} for this Firestore instance.
    */