Bug 1338011 - Adds some telemetry probes - f=bsmedberg r=gerald

MozReview-Commit-ID: BmwEjBiCBNo

--HG--
extra : rebase_source : 1d181a6dd1385304c6c45a22e99563f570e31374

gfx/ipc/GPUProcessManager.cpp

@@ -51,6 +51,13 @@ namespace gfx {
 
 using namespace mozilla::layers;
 
+enum class FallbackType : uint32_t
+{
+  NONE = 0,
+  DECODINGDISABLED,
+  DISABLED,
+};
+
 static StaticAutoPtr<GPUProcessManager> sSingleton;
 
 GPUProcessManager*
@@ -163,6 +170,9 @@ GPUProcessManager::DisableGPUProcess(const char* aMessage)
 
   gfxPlatform::NotifyGPUProcessDisabled();
 
+  Telemetry::Accumulate(Telemetry::GPU_PROCESS_CRASH_FALLBACKS,
+                        uint32_t(FallbackType::DISABLED));
+
   DestroyProcess();
   ShutdownVsyncIOThread();
 }
@@ -379,8 +389,14 @@ GPUProcessManager::OnProcessUnexpectedShutdown(GPUProcessHost* aHost)
     SprintfLiteral(disableMessage, "GPU process disabled after %d attempts",
                    mNumProcessAttempts);
     DisableGPUProcess(disableMessage);
-  } else if (mNumProcessAttempts > uint32_t(gfxPrefs::GPUProcessMaxRestartsWithDecoder())) {
+  } else if (mNumProcessAttempts > uint32_t(gfxPrefs::GPUProcessMaxRestartsWithDecoder()) &&
+             mDecodeVideoOnGpuProcess) {
     mDecodeVideoOnGpuProcess = false;
+    Telemetry::Accumulate(Telemetry::GPU_PROCESS_CRASH_FALLBACKS,
+                                     uint32_t(FallbackType::DECODINGDISABLED));
+  } else {
+    Telemetry::Accumulate(Telemetry::GPU_PROCESS_CRASH_FALLBACKS,
+                                     uint32_t(FallbackType::NONE));
   }
 
   HandleProcessLost();

toolkit/components/telemetry/Histograms.json

@@ -1152,6 +1152,15 @@
     "releaseChannelCollection": "opt-out",
     "description": "GPU process initialization (excluding XPCOM and fork time) time in milliseconds"
   },
+  "GPU_PROCESS_CRASH_FALLBACKS": {
+    "alert_emails": ["cpearce@mozilla.com", "gsquelart@mozilla.com"],
+    "expires_in_version": "60",
+    "bug_numbers": [1338011],
+    "kind": "enumerated",
+    "releaseChannelCollection": "opt-out",
+    "n_values":  10,
+    "description": "Count how often we use different fallbacks when the GPU process crashes: None=0, GPUProcessDecodingDisabled=1, GPUProcessDisabled=2"
+  },
   "JS_DEPRECATED_LANGUAGE_EXTENSIONS_IN_CONTENT": {
     "alert_emails": ["jdemooij@mozilla.com"],
     "expires_in_version": "never",