[Android] Add an option to view the tracing record categories when running from python script.

content/browser/android/tracing_controller_android.cc

Index: content/browser/android/tracing_controller_android.cc
diff --git a/content/browser/android/tracing_controller_android.cc b/content/browser/android/tracing_controller_android.cc
index 3c3ee756434fa57490f67648d142d139041fd99e..1d1478a9b880ae85d0a744982d89da12bedb6bb6 100644
--- a/content/browser/android/tracing_controller_android.cc
+++ b/content/browser/android/tracing_controller_android.cc
@@ -7,7 +7,9 @@
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/debug/trace_event.h"
+#include "base/json/json_writer.h"
 #include "base/logging.h"
+#include "base/memory/ref_counted_memory.h"
 #include "content/public/browser/tracing_controller.h"
 #include "jni/TracingControllerAndroid_jni.h"
 
@@ -76,6 +78,38 @@ void TracingControllerAndroid::OnTracingStopped(
     Java_TracingControllerAndroid_onTracingStopped(env, obj.obj());
 }
 
+bool TracingControllerAndroid::GetKnownCategoryGroupsAsync(JNIEnv* env,
+                                                           jobject obj) {
+  if (!TracingController::GetInstance()->GetCategories(
+          base::Bind(&TracingControllerAndroid::OnKnownCategoriesReceived,
+                     weak_factory_.GetWeakPtr()))) {
+    return false;
+  }
+  return true;
+}
+
+void TracingControllerAndroid::OnKnownCategoriesReceived(
+    const std::set<std::string>& categories_received) {

[Xianzhu, 2014/05/05 16:32:21]

As the Java side doesn't actually need the categories but just print a log
message for the python script, can we avoid going back to Java by printing a log
message here?

[r.kasibhatla, 2014/05/06 11:04:06]

Done.

+  JNIEnv* env = base::android::AttachCurrentThread();
+
+  scoped_ptr<base::ListValue> category_list(new base::ListValue());
+  for (std::set<std::string>::const_iterator it = categories_received.begin();
+       it != categories_received.end();
+       ++it) {
+    category_list->AppendString(*it);
+  }
+  base::RefCountedString* res = new base::RefCountedString();
+  base::JSONWriter::Write(category_list.get(), &res->data());
+
+  std::string received_category_list = res->data();
+  jstring category_list_as_json_string = base::android::ConvertUTF8ToJavaString(
+                                        env, received_category_list).Release();
+  base::android::ScopedJavaLocalRef<jobject> obj = weak_java_object_.get(env);
+  if (obj.obj())
+    Java_TracingControllerAndroid_onCategoryGroupsReceived(
+        env, obj.obj(), category_list_as_json_string);
+}
+
 static jstring GetDefaultCategories(JNIEnv* env, jobject obj) {
   return base::android::ConvertUTF8ToJavaString(env,
       base::debug::CategoryFilter::kDefaultCategoryFilterString).Release();