cmsdk: Mandate performance feature xml's for service implementation.

  The feature xml plays two roles:

      1) To allow sdk interface (constructor) to throw when system
      service is unavailable. This allows for clearer platform
      development debugging.

      2) To allow for simpler disambiguation of what services to
      instrument in a modular environment.

Change-Id: I50f5993ff9c5107fdeaa9a5aa95377235eb3ac02
TICKET: CYNGNOS-2294

2 files changed, 14 insertions, 1 deletions

diff --git a/src/java/cyanogenmod/app/CMContextConstants.java b/src/java/cyanogenmod/app/CMContextConstants.java
index 83a7c2d..e34f211 100644
--- a/src/java/cyanogenmod/app/CMContextConstants.java
+++ b/src/java/cyanogenmod/app/CMContextConstants.java
@@ -165,5 +165,13 @@ public final class CMContextConstants {
          */
         @SdkConstant(SdkConstant.SdkConstantType.FEATURE)
         public static final String THEMES = "org.cyanogenmod.theme";
+
+        /**
+         * Feature for {@link PackageManager#getSystemAvailableFeatures} and
+         * {@link PackageManager#hasSystemFeature}: The device includes the cm performance service
+         * utilized by the cmsdk.
+         */
+        @SdkConstant(SdkConstant.SdkConstantType.FEATURE)
+        public static final String PERFORMANCE = "org.cyanogenmod.performance";
     }
 }
diff --git a/src/java/cyanogenmod/power/PerformanceManager.java b/src/java/cyanogenmod/power/PerformanceManager.java
index 393e905..9b44399 100644
--- a/src/java/cyanogenmod/power/PerformanceManager.java
+++ b/src/java/cyanogenmod/power/PerformanceManager.java
@@ -78,7 +78,12 @@ public class PerformanceManager {
 
     private PerformanceManager(Context context) {
         sService = getService();
-
+        if (context.getPackageManager().hasSystemFeature(
+                CMContextConstants.Features.PERFORMANCE) && sService == null) {
+            throw new RuntimeException("Unable to get PerformanceManagerService. The service" +
+                    " either crashed, was not started, or the interface has been called to early" +
+                    " in SystemServer init");
+        }
         try {
             if (sService != null) {
                 mNumberOfProfiles = sService.getNumberOfProfiles();