Make DriverCrashGuard initialization lazy. (bug 1190281 part 3, r=mattwoodrow)

gfx/src/DriverCrashGuard.cpp

@@ -23,7 +23,24 @@ namespace gfx {
 bool DriverCrashGuard::sEnvironmentHasBeenUpdated = false;
 
 DriverCrashGuard::DriverCrashGuard()
- : mIsChromeProcess(XRE_GetProcessType() == GeckoProcessType_Default)
+ : mInitialized(false)
+ , mIsChromeProcess(XRE_GetProcessType() == GeckoProcessType_Default)
+{
+}
+
+void
+DriverCrashGuard::InitializeIfNeeded()
+{
+  if (mInitialized) {
+    return;
+  }
+
+  mInitialized = true;
+  Initialize();
+}
+
+void
+DriverCrashGuard::Initialize()
 {
   if (!mIsChromeProcess) {
     // We assume the parent process already performed crash detection for
@@ -76,8 +93,9 @@ DriverCrashGuard::~DriverCrashGuard()
 }
 
 bool
-DriverCrashGuard::DisableAcceleration() const
+DriverCrashGuard::Crashed()
 {
+  InitializeIfNeeded();
   return gfxPrefs::DriverInitStatus() == int32_t(DriverInitStatus::Recovered);
 }
 

gfx/src/DriverCrashGuard.h

@@ -28,13 +28,22 @@ enum class DriverInitStatus
   Recovered
 };
 
+// DriverCrashGuard is used to detect crashes at graphics driver callsites.
+// 
+// If the graphics environment is unrecognized or has changed since the last
+// session, the crash guard will activate and will detect any crashes within
+// the scope of the guard object.
+//
+// If a callsite has a previously encountered crash, and the environment has
+// not changed since the last session, then the guard will set a status flag
+// indicating that the driver should not be used.
 class DriverCrashGuard
 {
 public:
   DriverCrashGuard();
   ~DriverCrashGuard();
 
-  bool DisableAcceleration() const;
+  bool Crashed();
 
   // These are the values reported to Telemetry (GRAPHICS_DRIVER_STARTUP_TEST).
   // Values should not change; add new values to the end.
@@ -46,6 +55,8 @@ public:
   };
 
 private:
+  void InitializeIfNeeded();
+  void Initialize();
   bool InitLockFilePath();
   bool UpdateEnvironment();
   bool CheckAndUpdatePref(const char* aPrefName, const nsAString& aCurrentValue);
@@ -61,6 +72,7 @@ private:
   static bool sEnvironmentHasBeenUpdated;
 
 private:
+  bool mInitialized;
   bool mIsChromeProcess;
   nsCOMPtr<nsIGfxInfo> mGfxInfo;
   nsCOMPtr<nsIFile> mLockFile;

gfx/thebes/gfxWindowsPlatform.cpp

@@ -2184,7 +2184,7 @@ gfxWindowsPlatform::InitializeDevices()
   // effectively a parent-process only check, since the content process
   // cannot create a lock file.
   DriverCrashGuard detectCrashes;
-  if (detectCrashes.DisableAcceleration()) {
+  if (detectCrashes.Crashed()) {
     mAcceleration = FeatureStatus::Blocked;
     return;
   }