skpbench: add option for gpu timing

tools/gpu/TestContext.h

Index: tools/gpu/TestContext.h
diff --git a/tools/gpu/TestContext.h b/tools/gpu/TestContext.h
index ffa8cae8f9d76792d8e1a924500f396efb6f0861..07673e751fed9026e4c869d433882de67622654a 100644
--- a/tools/gpu/TestContext.h
+++ b/tools/gpu/TestContext.h
@@ -13,6 +13,8 @@
 #include "../private/SkGpuFenceSync.h"
 #include "../private/SkTemplates.h"
 
+class SkGpuTimer;
+
 namespace sk_gpu_test {
 /**
  * An offscreen 3D context. This class is intended for Skia's internal testing needs and not
@@ -25,6 +27,10 @@ public:
     virtual bool isValid() const = 0;
 
     bool fenceSyncSupport() const { return fFenceSync != nullptr; }
+    SkGpuFenceSync* fenceSync() const { SkASSERT(fFenceSync); return fFenceSync; }
+
+    bool gpuTimingSupport() const { return fGpuTimer != nullptr; }
+    SkGpuTimer* gpuTimer() const { SkASSERT(fGpuTimer); return fGpuTimer; }
 
     bool getMaxGpuFrameLag(int *maxFrameLag) const {
         if (!fFenceSync) {
@@ -73,13 +79,9 @@ public:
     /** Wait until all GPU work is finished. */
     virtual void finish() = 0;
 
-    /**
-     * returns the fencesync object owned by this GLTestContext
-     */
-    SkGpuFenceSync *fenceSync() { return fFenceSync; }
-
 protected:
-    SkGpuFenceSync* fFenceSync;
+    SkGpuFenceSync*   fFenceSync;
+    SkGpuTimer*       fGpuTimer;
 
     TestContext();