Add runtime flag to turn compressed alpha masks on

bench/nanobench.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <ctype.h>
 
 #include "Benchmark.h"
@@ skipping 38 matching lines @@
 }
 
 DEFINE_int32(loops, kDefaultLoops, loops_help_txt().c_str());
 
 DEFINE_int32(samples, 10, "Number of samples to measure for each bench.");
 DEFINE_int32(overheadLoops, 100000, "Loops to estimate timer overhead.");
 DEFINE_double(overheadGoal, 0.0001,
               "Loop until timer overhead is at most this fraction of our measurments.");
 DEFINE_double(gpuMs, 5, "Target bench time in millseconds for GPU.");
 DEFINE_int32(gpuFrameLag, 5, "Overestimate of maximum number of frames GPU allows to lag.");
+DEFINE_bool(gpuCompressAlphaMasks, false, "Compress masks generated from falling back to "
+                                          "software path rendering.");
 
 DEFINE_string(outResultsFile, "", "If given, write results here as JSON.");
 DEFINE_int32(maxCalibrationAttempts, 3,
              "Try up to this many times to guess loops for a bench, or skip the bench.");
 DEFINE_int32(maxLoops, 1000000, "Never run a bench more times than this.");
 DEFINE_string(key, "", "Space-separated key/value pairs to add to JSON.");
 DEFINE_string(gitHash, "", "Git hash to add to JSON.");
 
 DEFINE_string(clip, "0,0,1000,1000", "Clip for SKPs.");
 DEFINE_string(scales, "1.0", "Space-separated scales for SKPs.");
@@ skipping 453 matching lines @@
     int fCurrentScale;
     int fCurrentSKP;
 };
 
 int nanobench_main();
 int nanobench_main() {
     SetupCrashHandler();
     SkAutoGraphics ag;
 
 #if SK_SUPPORT_GPU
-    gGrFactory.reset(SkNEW_ARGS(GrContextFactory, (GrContext::Options())));
+    GrContext::Options grContextOpts;
+    grContextOpts.fDrawPathToCompressedTexture = FLAGS_gpuCompressAlphaMasks;
+    gGrFactory.reset(SkNEW_ARGS(GrContextFactory, (grContextOpts)));
 #endif
 
     if (kAutoTuneLoops != FLAGS_loops) {
         FLAGS_samples     = 1;
         FLAGS_gpuFrameLag = 0;
     }
 
     if (!FLAGS_writePath.isEmpty()) {
         SkDebugf("Writing files to %s.\n", FLAGS_writePath[0]);
         if (!sk_mkdir(FLAGS_writePath[0])) {
@@ skipping 142 matching lines @@
 
     return 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return nanobench_main();
 }
 #endif