When the sanity test fails, report its snapshot via Telemetry. (bug 1194505, r=mattwoodrow,vladan)

toolkit/components/gfx/SanityTest.js

@@ -74,6 +74,16 @@ function reportTestReason(val) {
   histogram.add(val);
 }
 
+function reportSnapshotContents(canvas) {
+  try {
+    var data = canvas.toDataURL();
+    Cc['@mozilla.org/observer-service;1'].
+        getService(Ci.nsIObserverService).
+        notifyObservers(null, "graphics-sanity-test-failed", data);
+  } catch (e) {
+  }
+}
+
 function annotateCrashReport(value) {
   try {
     // "1" if we're annotating the crash report, "" to remove the annotation.
@@ -167,7 +177,9 @@ let listener = {
 
     // Perform the compositor backbuffer test, which currently we use for
     // actually deciding whether to enable hardware media decoding.
-    testCompositor(this.win, this.ctx);
+    if (!testCompositor(this.win, this.ctx)) {
+      reportSnapshotContents(this.canvas);
+    }
 
     this.endTest();
   },

toolkit/components/telemetry/TelemetryEnvironment.jsm

@@ -161,6 +161,7 @@ const EXPERIMENTS_CHANGED_TOPIC = "experiments-changed";
 const SEARCH_ENGINE_MODIFIED_TOPIC = "browser-search-engine-modified";
 const SEARCH_SERVICE_TOPIC = "browser-search-service";
 const COMPOSITOR_CREATED_TOPIC = "compositor:created";
+const SANITY_TEST_FAILED_TOPIC = "graphics-sanity-test-failed";
 
 /**
  * Get the current browser.
@@ -814,6 +815,7 @@ EnvironmentCache.prototype = {
     Services.obs.addObserver(this, SEARCH_ENGINE_MODIFIED_TOPIC, false);
     Services.obs.addObserver(this, SEARCH_SERVICE_TOPIC, false);
     Services.obs.addObserver(this, COMPOSITOR_CREATED_TOPIC, false);
+    Services.obs.addObserver(this, SANITY_TEST_FAILED_TOPIC, false);
   },
 
   _removeObservers: function () {
@@ -821,6 +823,7 @@ EnvironmentCache.prototype = {
     Services.obs.removeObserver(this, SEARCH_ENGINE_MODIFIED_TOPIC);
     Services.obs.removeObserver(this, SEARCH_SERVICE_TOPIC);
     Services.obs.removeObserver(this, COMPOSITOR_CREATED_TOPIC);
+    Services.obs.removeObserver(this, SANITY_TEST_FAILED_TOPIC);
   },
 
   observe: function (aSubject, aTopic, aData) {
@@ -846,6 +849,9 @@ EnvironmentCache.prototype = {
         // first compositor to be created and then query nsIGfxInfo again.
         this._onCompositorCreated();
         break;
+      case SANITY_TEST_FAILED_TOPIC:
+        this._onGraphicsSanityTestFailed(aData);
+        break;
     }
   },
 
@@ -925,6 +931,11 @@ EnvironmentCache.prototype = {
     }
   },
 
+  _onGraphicsSanityTestFailed: function (aData) {
+    let gfxData = this._currentEnvironment.system.gfx;
+    gfxData.sanityTestSnapshot = aData;
+  },
+
   /**
    * Get the build data in object form.
    * @return Object containing the build data.