add testing flag to force rasterpipeline

Bug: skia:
Change-Id: I8e195e90dc00b9be9072858086f7541e993428da
Reviewed-on: https://skia-review.googlesource.com/18585
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/bench/nanobench.cpp b/bench/nanobench.cpp
index ca8c183..b6f8343 100644
--- a/bench/nanobench.cpp
+++ b/bench/nanobench.cpp
@@ -50,6 +50,8 @@
 
 #include <stdlib.h>
 
+extern bool gSkForceRasterPipelineBlitter;
+
 #ifndef SK_BUILD_FOR_WIN32
     #include <unistd.h>
 #endif
@@ -128,6 +130,8 @@
 DEFINE_string(benchType,  "",
         "Apply usual --match rules to bench type: micro, recording, piping, playback, skcodec, etc.");
 
+DEFINE_bool(forceRasterPipeline, false, "sets gSkForceRasterPipelineBlitter");
+
 #if SK_SUPPORT_GPU
 DEFINE_pathrenderer_flag;
 #endif
@@ -1196,6 +1200,9 @@
     if (FLAGS_forceAnalyticAA) {
         gSkForceAnalyticAA = true;
     }
+    if (FLAGS_forceRasterPipeline) {
+        gSkForceRasterPipelineBlitter = true;
+    }
 
     int runs = 0;
     BenchmarkStream benchStream;