attempt to resolve before a build

Due to changes in newer versions of Unity, plugin modules are not reloaded
before build and this meant that some of our optimizations to resolve
only when necessary didn't work as expected. With this fix, we will be
running a resolve every build (provided there were no build errors in prior
attempts), and also run it only on one scene for a build with multiple scenes.
Jetifier enabling via gradle properties wasn't flagged as a build setting that
is checked for differences during "are there differences for a new resolve?".

Bug: 170395178
Fixes: #810
Change-Id: I2b8994497bf48c2eb6276137289927859e10f64f

Author: vimanyu

source/AndroidResolver/src/PlayServicesResolver.cs

@@ -1152,6 +1152,18 @@ private static void OnPostprocessAllAssets(string[] importedAssets,
         /// </summary>
         private static int scenesProcessed = 0;
 
+        /// <summary>
+        /// Reset static variable after every successful build.
+        /// </summary>
+        [UnityEditor.Callbacks.PostProcessBuildAttribute(0)]
+        private static void OnPostProcessBuild(UnityEditor.BuildTarget target, string path) {
+            // Since certain versions of Unity do not reload the module, we want
+            // to reset this variable in order to allow an attempt to resolve in OnPostProcessScene().
+            // Caveat: Unity calls this only after a successful build. We should really be calling
+            // this after every build (successful or not).
+            scenesProcessed = 0;
+        }
+
         /// <summary>
         /// If auto-resolution is enabled, run resolution synchronously before building the
         /// application.
@@ -1171,6 +1183,8 @@ private static void OnPostProcessScene() {
             if (scenesProcessed > 1) return;
             Log("Starting auto-resolution before scene build...", level: LogLevel.Verbose);
             bool success = ResolveSync(false, true);
+            // If resolve fails, we want to try the resolve next time around.
+            if(!success) scenesProcessed--;
             Log(String.Format("Android resolution {0}.", success ? "succeeded" : "failed"),
                     level: LogLevel.Verbose);
         }
@@ -2475,6 +2489,7 @@ internal static Dictionary<string, string> GetResolutionSettings() {
                 {"bundleId", GetAndroidApplicationId()},
                 {"gradleBuildEnabled", buildSystemSettings.GradleBuildEnabled.ToString()},
                 {"gradleTemplateEnabled", buildSystemSettings.GradleTemplateEnabled.ToString()},
+                {"gradlePropertiesTemplateEnabled", buildSystemSettings.GradlePropertiesTemplateEnabled.ToString()},
                 {"projectExportEnabled", buildSystemSettings.ProjectExportEnabled.ToString()},
                 {"androidAbis", androidAbis.ToString()},
             };