Benchmark: `--save-all-traces` argument Benchmark: Replace `--save-trace` argument by `--save-all-traces`. It outputs a .trace file per benchmark as before, but stores all traces, without filtering by the measurements defined in the benchmarks file. fixes #458 BUG= R=etiennej@chromium.org, ppi@chromium.org, qsr@chromium.org Review URL: https://codereview.chromium.org/1391013005 .

diff --git a/apps/benchmark/benchmark_app.cc b/apps/benchmark/benchmark_app.cc
index bfdc299..c467d4d 100644
--- a/apps/benchmark/benchmark_app.cc
+++ b/apps/benchmark/benchmark_app.cc

@@ -44,17 +44,13 @@
       return;
     }
 
-    // Calculate a list of trace categories we want to collect: a union of all
-    // categories targeted in measurements.
-    std::set<std::string> category_set;
-    for (const Measurement& measurement : args_.measurements) {
-      std::vector<std::string> categories;
-      base::SplitString(measurement.target_event.categories, ',', &categories);
-      category_set.insert(categories.begin(), categories.end());
+    // Don't compute the categories string if all categories should be traced.
+    std::string categories_str;
+    if (args_.write_output_file) {
+      categories_str = "*";
+    } else {
+      categories_str = ComputeCategoriesStr();
     }
-    std::vector<std::string> unique_categories(category_set.begin(),
-                                               category_set.end());
-    std::string categories_str = JoinString(unique_categories, ',');
 
     // Connect to trace collector, which will fetch the trace events produced by
     // the app being benchmarked.
@@ -66,12 +62,25 @@
 
     // Start tracing the application with 1 sec of delay.
     base::MessageLoop::current()->PostDelayedTask(
-        FROM_HERE,
-        base::Bind(&BenchmarkApp::StartTracedApplication,
-            base::Unretained(this), app),
+        FROM_HERE, base::Bind(&BenchmarkApp::StartTracedApplication,
+                              base::Unretained(this), app),
         base::TimeDelta::FromSeconds(1));
   }
 
+  // Computes the string of trace categories we want to collect: a union of all
+  // categories targeted in measurements.
+  std::string ComputeCategoriesStr() {
+    std::set<std::string> category_set;
+    for (const Measurement& measurement : args_.measurements) {
+      std::vector<std::string> categories;
+      base::SplitString(measurement.target_event.categories, ',', &categories);
+      category_set.insert(categories.begin(), categories.end());
+    }
+    std::vector<std::string> unique_categories(category_set.begin(),
+                                               category_set.end());
+    return JoinString(unique_categories, ',');
+  }
+
   void StartTracedApplication(mojo::ApplicationImpl* app) {
     // Record the time origin for measurements just before connecting to the app
     // being benchmarked.

diff --git a/mojo/devtools/common/mojo_benchmark b/mojo/devtools/common/mojo_benchmark
index fc0258e..8f83c5b 100755
--- a/mojo/devtools/common/mojo_benchmark
+++ b/mojo/devtools/common/mojo_benchmark

@@ -148,7 +148,7 @@
       description=_DESCRIPTION)
   parser.add_argument('benchmark_list_file', type=file,
                       help='a file listing benchmarks to run')
-  parser.add_argument('--save-traces', action='store_true',
+  parser.add_argument('--save-all-traces', action='store_true',
                       help='save the traces produced by benchmarks to disk')
   perf_dashboard.add_argparse_server_arguments(parser)
 
@@ -179,7 +179,7 @@
       measurements = variant_spec['measurements']
 
       output_file = None
-      if script_args.save_traces:
+      if script_args.save_all_traces:
         output_file = 'benchmark-%s-%s-%s.trace' % (
             benchmark_name.replace(' ', '_'),
             variant_name.replace(' ', '_'),