Collect tab timing information for use in telementry-based startup tests

content/renderer/stats_collection_controller.cc

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/renderer/stats_collection_controller.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/json/json_writer.h"
+#include "base/metrics/histogram.h"
+#include "base/metrics/statistics_recorder.h"
+#include "base/string_util.h"
+#include "content/common/child_process_messages.h"
+#include "content/renderer/render_view_impl.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebFrame.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
+
+using webkit_glue::CppArgumentList;
+using webkit_glue::CppVariant;
+
+namespace content {
+
+namespace {
+
+bool CurrentRenderViewImpl(RenderViewImpl** out) {
+  WebKit::WebFrame* web_frame = WebKit::WebFrame::frameForCurrentContext();
+  if (!web_frame)
+    return false;
+
+  WebKit::WebView* web_view = web_frame->view();
+  if (!web_view)
+    return false;
+
+  RenderViewImpl* render_view_impl =
+      RenderViewImpl::FromWebView(web_view);
+  if (!render_view_impl)
+    return false;
+
+  *out = render_view_impl;
+  return true;
+}
+
+// Encodes a WebContentsLoadTime as JSON.
+// Input:
+// - |load_start_time| - time at which page load started.
+// - |load_stop_time| - time at which page load stopped.
+// - |result| - returned JSON.
+// Example return value:
+// {'load_start_ms': 1, 'load_duration_ms': 2.5}
+// either value may be null if a web contents hasn't fully loaded.
+// load_start_ms is represented as milliseconds since system boot.
+void ConvertLoadTimeToJSON(
+    const base::TimeTicks& load_start_time,
+    const base::TimeTicks& load_stop_time,
+    std::string *result) {
+  DictionaryValue item;
+
+  if (load_start_time.is_null()) {
+     item.Set("load_start_ms", Value::CreateNullValue());
+  } else {
+    // This code relies on an implementation detail of TimeTicks::Now() - that
+    // its return value happens to coincide with the system uptime value in
+    // microseconds, on Win/Mac/iOS/Linux/ChromeOS and Android.  See comments
+    // in base::SysInfo::Uptime().
+    item.SetDouble("load_start_ms", load_start_time.ToInternalValue() / 1000);
+  }
+  if (load_stop_time.is_null() || load_stop_time.is_null()) {
+    item.Set("load_duration_ms", Value::CreateNullValue());
+  } else {
+    item.SetDouble("load_duration_ms",
+        (load_stop_time - load_start_time).InMilliseconds());
+  }
+  base::JSONWriter::Write(&item, result);
+}
+
+}  // namespace
+
+StatsCollectionController::StatsCollectionController()
+    : sender_(NULL) {
+  BindCallback("getHistogram",
+               base::Bind(&StatsCollectionController::GetHistogram,
+                          base::Unretained(this)));
+  BindCallback("getBrowserHistogram",
+               base::Bind(&StatsCollectionController::GetBrowserHistogram,
+                          base::Unretained(this)));
+  BindCallback("tabLoadTiming",
+               base::Bind(
+                  &StatsCollectionController::GetTabLoadTiming,
+                  base::Unretained(this)));
+}
+
+void StatsCollectionController::GetHistogram(const CppArgumentList& args,
+                                            CppVariant* result) {
+  if (args.size() != 1) {
+    result->SetNull();
+    return;
+  }
+  base::HistogramBase* histogram =
+      base::StatisticsRecorder::FindHistogram(args[0].ToString());
+  std::string output;
+  if (!histogram) {
+    output = "{}";
+  } else {
+    histogram->WriteJSON(&output);
+  }
+  result->Set(output);
+}
+
+void StatsCollectionController::GetBrowserHistogram(const CppArgumentList& args,
+                                                   CppVariant* result) {
+  if (args.size() != 1) {
+    result->SetNull();
+    return;
+  }
+
+  if (!sender_) {
+    NOTREACHED();
+    result->SetNull();
+    return;
+  }
+
+  std::string histogram_json;
+  sender_->Send(new ChildProcessHostMsg_GetBrowserHistogram(
+      args[0].ToString(), &histogram_json));
+  result->Set(histogram_json);
+}
+
+void StatsCollectionController::GetTabLoadTiming(
+    const CppArgumentList& args,
+    CppVariant* result) {
+  if (!sender_) {
+    NOTREACHED();
+    result->SetNull();
+    return;
+  }
+
+  RenderViewImpl *render_view_impl = NULL;
+  if (!CurrentRenderViewImpl(&render_view_impl)) {
+    NOTREACHED();
+    result->SetNull();
+    return;
+  }
+
+  StatsCollectionObserver* observer =
+      render_view_impl->GetStatsCollectionObserver();
+  if (!observer) {
+    NOTREACHED();
+    result->SetNull();
+    return;
+  }
+
+  std::string tab_timing_json;
+  ConvertLoadTimeToJSON(
+      observer->load_start_time(), observer->load_stop_time(),
+      &tab_timing_json);
+  result->Set(tab_timing_json);
+}
+
+}  // namespace content