Added trace query code and wired tracing through BrowserProxy so tests can run traces.

chrome/browser/automation/testing_automation_provider.cc

Index: chrome/browser/automation/testing_automation_provider.cc
diff --git a/chrome/browser/automation/testing_automation_provider.cc b/chrome/browser/automation/testing_automation_provider.cc
index 6e45cf21c843601616c89d5d940217dadc784200..b95210950a17289bc6ac1eada8c796601aefee6a 100644
--- a/chrome/browser/automation/testing_automation_provider.cc
+++ b/chrome/browser/automation/testing_automation_provider.cc
@@ -251,6 +251,35 @@ void TestingAutomationProvider::Observe(int type,
   Release();
 }
 
+void TestingAutomationProvider::OnEndTracingComplete() {
+  IPC::Message* reply_message = tracing_data_.reply_message.release();
+  if (reply_message) {
+    // Finish off JSON string.
+    if (tracing_data_.json_output.empty())
+      tracing_data_.json_output.push_back("[]");
+    else
+      tracing_data_.json_output.push_back("]");
+    AutomationMsg_EndTracing::WriteReplyParams(reply_message, true);
+    Send(reply_message);
+  }
+}
+
+void TestingAutomationProvider::OnTraceDataCollected(
+    const std::string& json_events) {
+  // |json_events| should start with '[' and end with ']'.
+  if (json_events.size() > 2) {
+    std::string chunk;
+    // If this is the first chunk, JSON starts with '['.
+    if (tracing_data_.json_output.empty())
+      chunk += '[';
+    else
+      chunk += ',';
+    chunk += json_events.substr(1, json_events.size() - 2);
+    // Append without the leading and trailing brackets.
+    tracing_data_.json_output.push_back(chunk);
+  }
+}
+
 bool TestingAutomationProvider::OnMessageReceived(
     const IPC::Message& message) {
   bool handled = true;
@@ -311,6 +340,9 @@ bool TestingAutomationProvider::OnMessageReceived(
     IPC_MESSAGE_HANDLER(AutomationMsg_Type, GetType)
     IPC_MESSAGE_HANDLER(AutomationMsg_IsBrowserInApplicationMode,
                         IsBrowserInApplicationMode)
+    IPC_MESSAGE_HANDLER(AutomationMsg_BeginTracing, BeginTracing)
+    IPC_MESSAGE_HANDLER_DELAY_REPLY(AutomationMsg_EndTracing, EndTracing)
+    IPC_MESSAGE_HANDLER(AutomationMsg_GetTracingOutput, GetTracingOutput)
     IPC_MESSAGE_HANDLER(AutomationMsg_Tab, GetTab)
     IPC_MESSAGE_HANDLER(AutomationMsg_TabProcessID, GetTabProcessID)
     IPC_MESSAGE_HANDLER(AutomationMsg_TabTitle, GetTabTitle)
@@ -1197,6 +1229,45 @@ void TestingAutomationProvider::IsBrowserInApplicationMode(int handle,
   }
 }
 
+void TestingAutomationProvider::BeginTracing(
+    const std::vector<std::string>& included_categories,
+    const std::vector<std::string>& excluded_categories,
+    bool* result) {
+  tracing_data_.json_output.clear();
+  *result = TraceController::GetInstance()->BeginTracing(this,
+                                                         included_categories,
+                                                         excluded_categories);
+}
+
+void TestingAutomationProvider::EndTracing(IPC::Message* reply_message) {
+  bool success = false;
+  if (!tracing_data_.reply_message.get()) {
+    success = TraceController::GetInstance()->EndTracingAsync(this);
+  }
+  // If failed to call EndTracingAsync, need to reply with failure now.
+  if (!success) {
+    AutomationMsg_EndTracing::WriteReplyParams(reply_message, false);
+    Send(reply_message);
+  } else {
+    // Defer EndTracing reply until the we are notified by TraceController.
+    tracing_data_.reply_message.reset(reply_message);
+  }
+}
+
+void TestingAutomationProvider::GetTracingOutput(std::string* chunk,
+                                                 int* remaining_chunks) {
+  // The JSON data is sent back to the test in chunks, because IPC sends will
+  // fail if they are too large.
+  if (tracing_data_.json_output.empty()) {
+    *chunk = "";
+    *remaining_chunks = -1;
+  } else {
+    *chunk = tracing_data_.json_output.front();
+    tracing_data_.json_output.pop_front();
+    *remaining_chunks = tracing_data_.json_output.size();
+  }
+}
+
 void TestingAutomationProvider::GetTab(int win_handle,
                                        int tab_index,
                                        int* tab_handle) {