Bug 1256290 - isGPUActive for the second graphics adapter doesn't work correctly, and this also means we should tighten up getGfxField a little bit r=gfritzsche

MozReview-Commit-ID: 3384RChTh2A

--HG--
extra : rebase_source : 01f0a56909784cc04415714b373fadfdb68eadf8
extra : histedit_source : 1f17971cd4828cc73fb9f306c92c01e5f5eccda7

toolkit/components/telemetry/TelemetryEnvironment.jsm

@@ -265,7 +265,7 @@ function getGfxField(aPropertyName, aDefault) {
   try {
     // Accessing the field may throw if |aPropertyName| does not exist.
     let gfxProp = gfxInfo[aPropertyName];
-    if (gfxProp !== "") {
+    if (gfxProp !== undefined && gfxProp !== "") {
       return gfxProp;
     }
   } catch (e) {}
@@ -1316,7 +1316,7 @@ EnvironmentCache.prototype = {
     this._log.trace("_getGFXData - Two display adapters detected.");
 
     gfxData.adapters.push(getGfxAdapter("2"));
-    gfxData.adapters[1].GPUActive = getGfxField("isGPU2Active ", null);
+    gfxData.adapters[1].GPUActive = getGfxField("isGPU2Active", null);
 
     return gfxData;
   },