cc: Add message passing mechanism to micro benchmarking.

cc/debug/micro_benchmark_controller.cc

Index: cc/debug/micro_benchmark_controller.cc
diff --git a/cc/debug/micro_benchmark_controller.cc b/cc/debug/micro_benchmark_controller.cc
index 7d9025c1c42103dc40f9499fc2b467ca8b827460..f6df0f6be19ac20aa997f0b9d2f7aece8086cec2 100644
--- a/cc/debug/micro_benchmark_controller.cc
+++ b/cc/debug/micro_benchmark_controller.cc
@@ -4,6 +4,7 @@
 
 #include "cc/debug/micro_benchmark_controller.h"
 
+#include <limits>
 #include <string>
 
 #include "base/callback.h"
@@ -17,6 +18,8 @@
 
 namespace cc {
 
+int MicroBenchmarkController::next_id_ = 1;
+
 namespace {
 
 scoped_ptr<MicroBenchmark> CreateBenchmark(
@@ -56,16 +59,37 @@ MicroBenchmarkController::MicroBenchmarkController(LayerTreeHost* host)
 
 MicroBenchmarkController::~MicroBenchmarkController() {}
 
-bool MicroBenchmarkController::ScheduleRun(
+int MicroBenchmarkController::ScheduleRun(
     const std::string& micro_benchmark_name,
     scoped_ptr<base::Value> value,
     const MicroBenchmark::DoneCallback& callback) {
   scoped_ptr<MicroBenchmark> benchmark =
       CreateBenchmark(micro_benchmark_name, value.Pass(), callback);
   if (benchmark.get()) {
+    int id = GetNextIdAndIncrement();
+    benchmark->set_id(id);
     benchmarks_.push_back(benchmark.Pass());
     host_->SetNeedsCommit();
-    return true;
+    return id;
+  }
+  return 0;
+}
+
+int MicroBenchmarkController::GetNextIdAndIncrement() {
+  int id = next_id_++;
+  // Wrap around to 1 if we overflow (very unlikely).
+  if (next_id_ == std::numeric_limits<int>::max())
+    next_id_ = 1;
+  return id;
+}
+
+bool MicroBenchmarkController::SendMessage(int id,
+                                           scoped_ptr<base::Value> value) {
+  for (ScopedPtrVector<MicroBenchmark>::iterator it = benchmarks_.begin();
+       it != benchmarks_.end();
+       ++it) {
+    if ((*it)->id() == id)
+      return (*it)->ProcessMessage(value.Pass());
   }
   return false;
 }