Revert of Make the Sk GL context class an abstract base class

tools/timer/GpuTimer.cpp

Index: tools/timer/GpuTimer.cpp
diff --git a/tools/timer/GpuTimer.cpp b/tools/timer/GpuTimer.cpp
index 0fdd9999226542824909cb873b4ac9cbe3af3fc9..aac10a3b0796b82b93e23ff2c80fc4c49d5de749 100644
--- a/tools/timer/GpuTimer.cpp
+++ b/tools/timer/GpuTimer.cpp
@@ -6,10 +6,10 @@
  * found in the LICENSE file.
  */
 #include "GpuTimer.h"
-#include "gl/SkGLContext.h"
+#include "gl/SkGLContextHelper.h"
 #include "gl/GrGLUtil.h"
 
-GpuTimer::GpuTimer(const SkGLContext* glctx) : fContext(glctx) {
+GpuTimer::GpuTimer(const SkGLContextHelper* glctx) : fContext(glctx) {
     if (fContext) {
         fContext->ref();
         fContext->makeCurrent();